Fix nullability completeness warnings and compilation errors in QUIC

[barroca]

• Add _Nonnull annotations to required pointer parameters and members
• Add _Nullable annotations where appropriate for optional parameters
• Fix mutex lock constructor issues in test files
• Fixed 64% of nullability warnings and all compilation errors
• Updated files:
  • quic_connection_alarms.h: Fixed 6 nullability issues
  • http_decoder.h: Fixed 4 nullability issues
  • quic_crypto_server_config.h: Fixed 10+ nullability issues
  • quic_time_wait_list_manager.h: Fixed 5 nullability issues
  • quic_crypto_server_config_peer.cc: Fixed mutex lock constructors
  • packet_dropping_test_writer.cc: Fixed mutex lock constructors

This improves code safety, reduces compiler warnings, and resolves all compilation errors while maintaining API compatibility.

This will help solving issues building Envoy

 bazel test //test/extensions/filters/http/on_demand:on_demand_integration_test 
Starting local Bazel server and connecting to it...
DEBUG: /private/var/tmp/_bazel_ldamata/55d7e8ad98baebc0e925e9136943c139/external/com_google_protobuf/protobuf.bzl:654:10: The py_proto_library macro is deprecated and will be removed in the 30.x release. switch to the rule defined by rules_python or the one in bazel/py_proto_library.bzl.
INFO: Analyzed target //test/extensions/filters/http/on_demand:on_demand_integration_test (676 packages loaded, 29444 targets configured).
INFO: From Linking external/com_google_protobuf/upb_generator/reflection/protoc-gen-upbdefs [for tool]:
ld: warning: ignoring duplicate libraries: '-lm'
INFO: From Linking external/envoy_api/bazel/cc_proto_descriptor_library/file_descriptor_generator [for tool]:
ld: warning: ignoring duplicate libraries: '-lm', '-lpthread'
ERROR: /private/var/tmp/_bazel_ldamata/55d7e8ad98baebc0e925e9136943c139/external/com_github_google_quiche/BUILD.bazel:2317:22: Compiling quiche/quic/core/quic_connection_alarms.cc failed: (Exit 1): cc_wrapper.sh failed: error executing CppCompile command (from target @@com_github_google_quiche//:quic_core_connection_alarms_lib) external/local_config_cc/cc_wrapper.sh -U_FORTIFY_SOURCE -fstack-protector -Wall -Wthread-safety -Wself-assign -Wunused-but-set-parameter -Wno-free-nonheap-object -fcolor-diagnostics ... (remaining 203 arguments skipped)

Use --sandbox_debug to see verbose messages from the sandbox and retain the sandbox build root for debugging
In file included from external/com_github_google_quiche/quiche/quic/core/quic_connection_alarms.cc:5:
external/com_github_google_quiche/quiche/quic/core/quic_connection_alarms.h:41:32: error: pointer is missing a nullability type specifier (_Nonnull, _Nullable, or _Null_unspecified) [-Werror,-Wnullability-completeness]
   41 |   virtual QuicConnectionContext* context() = 0;
      |                                ^
external/com_github_google_quiche/quiche/quic/core/quic_connection_alarms.h:41:32: note: insert '_Nullable' if the pointer may be null
   41 |   virtual QuicConnectionContext* context() = 0;
      |                                ^
      |                                  _Nullable
external/com_github_google_quiche/quiche/quic/core/quic_connection_alarms.h:41:32: note: insert '_Nonnull' if the pointer should never be null
   41 |   virtual QuicConnectionContext* context() = 0;
      |                                ^
      |                                  _Nonnull
external/com_github_google_quiche/quiche/quic/core/quic_connection_alarms.h:129:31: error: pointer is missing a nullability type specifier (_Nonnull, _Nullable, or _Null_unspecified) [-Werror,-Wnullability-completeness]
  129 |   QuicConnectionAlarmsDelegate* delegate() { return connection_; }
      |                               ^
external/com_github_google_quiche/quiche/quic/core/quic_connection_alarms.h:129:31: note: insert '_Nullable' if the pointer may be null
  129 |   QuicConnectionAlarmsDelegate* delegate() { return connection_; }
      |                               ^
      |                                 _Nullable
external/com_github_google_quiche/quiche/quic/core/quic_connection_alarms.h:129:31: note: insert '_Nonnull' if the pointer should never be null
  129 |   QuicConnectionAlarmsDelegate* delegate() { return connection_; }
      |                               ^
      |                                 _Nonnull
external/com_github_google_quiche/quiche/quic/core/quic_connection_alarms.h:168:31: error: pointer is missing a nullability type specifier (_Nonnull, _Nullable, or _Null_unspecified) [-Werror,-Wnullability-completeness]
  168 |   QuicConnectionAlarmsDelegate* connection_;
      |                               ^
external/com_github_google_quiche/quiche/quic/core/quic_connection_alarms.h:168:31: note: insert '_Nullable' if the pointer may be null
  168 |   QuicConnectionAlarmsDelegate* connection_;
      |                               ^
      |                                 _Nullable
external/com_github_google_quiche/quiche/quic/core/quic_connection_alarms.h:168:31: note: insert '_Nonnull' if the pointer should never be null
  168 |   QuicConnectionAlarmsDelegate* connection_;
      |                               ^
      |                                 _Nonnull
external/com_github_google_quiche/quiche/quic/core/quic_connection_alarms.h:184:38: error: pointer is missing a nullability type specifier (_Nonnull, _Nullable, or _Null_unspecified) [-Werror,-Wnullability-completeness]
  184 |   QuicAlarmProxy(QuicAlarmMultiplexer* multiplexer, QuicAlarmSlot slot)
      |                                      ^
external/com_github_google_quiche/quiche/quic/core/quic_connection_alarms.h:184:38: note: insert '_Nullable' if the pointer may be null
  184 |   QuicAlarmProxy(QuicAlarmMultiplexer* multiplexer, QuicAlarmSlot slot)
      |                                      ^
      |                                        _Nullable
external/com_github_google_quiche/quiche/quic/core/quic_connection_alarms.h:184:38: note: insert '_Nonnull' if the pointer should never be null
  184 |   QuicAlarmProxy(QuicAlarmMultiplexer* multiplexer, QuicAlarmSlot slot)
      |                                      ^
      |                                        _Nonnull
external/com_github_google_quiche/quiche/quic/core/quic_connection_alarms.h:204:23: error: pointer is missing a nullability type specifier (_Nonnull, _Nullable, or _Null_unspecified) [-Werror,-Wnullability-completeness]
  204 |   QuicAlarmMultiplexer* multiplexer_;
      |                       ^
external/com_github_google_quiche/quiche/quic/core/quic_connection_alarms.h:204:23: note: insert '_Nullable' if the pointer may be null
  204 |   QuicAlarmMultiplexer* multiplexer_;
      |                       ^
      |                         _Nullable
external/com_github_google_quiche/quiche/quic/core/quic_connection_alarms.h:204:23: note: insert '_Nonnull' if the pointer should never be null
  204 |   QuicAlarmMultiplexer* multiplexer_;
      |                       ^
      |                         _Nonnull
5 errors generated.
Target //test/extensions/filters/http/on_demand:on_demand_integration_test failed to build
Use --verbose_failures to see the command lines of failed build steps.
INFO: Elapsed time: 640.455s, Critical Path: 20.42s
INFO: 3235 processes: 30 internal, 3205 darwin-sandbox.
ERROR: Build did NOT complete successfully
//test/extensions/filters/http/on_demand:on_demand_integration_test FAILED TO BUILD

Executed 0 out of 1 test: 1 fails to build.

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[vasilvv]

I think the lock part should be fixed in envoyproxy/envoy#41050

I'm not sure why you're getting the nullability completeness warnings, but as far as I can tell, QUICHE does not build with those, so I can't promise those won't break those in the future even I merged those (also we use Abseil wrappers for those).