Fix module reload in the presence of file delete or rename

[jurgenvinju]

• don't crash without proper error message during reload if a file has dissappeared
• solve confusing getLocation method name on Environment
• check for other broken uses of getLocation
• clarify error messages for missing modules who were imported or extended before the reloader started.
• manually test happy flow for module reload, directly and indirectly
• manually test reload with missing imports directly from the top level shell (via file rename)
• manually test reload with missing imports indirectly via imports via imports (via file rename)

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[codecov]

Codecov Report

❌ Patch coverage is 30.00000% with 14 lines in your changes missing coverage. Please review.
✅ Project coverage is 46%. Comparing base (98c58e4) to head (b04f485).
⚠️ Report is 31 commits behind head on main.

Files with missing lines	Patch %	Lines
src/org/rascalmpl/interpreter/Evaluator.java	16%	9 Missing and 1 partial ⚠️
src/org/rascalmpl/interpreter/utils/Profiler.java	0%	3 Missing ⚠️
src/org/rascalmpl/semantics/dynamic/Import.java	0%	1 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##              main   #2660   +/-   ##
=======================================
- Coverage       46%     46%   -1%     
+ Complexity    6682    6678    -4     
=======================================
  Files          795     795           
  Lines        65892   65895    +3     
  Branches      9877    9879    +2     
=======================================
- Hits         30710   30699   -11     
- Misses       32810   32821   +11     
- Partials      2372    2375    +3     

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[toinehartman]

Thanks for fixing this properly! Tested successful reloading and 'reloading' a removed module. The warnings now nicely indicate the cause of the warning as well. LGTM.