False "all tests passed!" report when browser fails to launch

[hlovdal]

Failure to launch the test browser is not properly detected as failure:

npx web-test-runner "test/*.js"
Need to install the following packages:
web-test-runner@0.0.36
Ok to proceed? (y) y

npm warn deprecated ...

test/agent-base.js:

 ❌ Failed to run test file:
      error: Browser did not start after 30000ms.

test/basic.js:

 ❌ Failed to run test file:
      error: Browser did not start after 30000ms.

test/content-type.js:

 ❌ Failed to run test file:
      error: Browser did not start after 30000ms.

test/form.js:

 ❌ Failed to run test file:
      error: Browser did not start after 30000ms.

test/json.js:

 ❌ Failed to run test file:
      error: Browser did not start after 30000ms.

test/redirects.js:

 ❌ Failed to run test file:
      error: Browser did not start after 30000ms.

test/request.js:

 ❌ Failed to run test file:
      error: Browser did not start after 30000ms.

test/retry.js:

 ❌ Failed to run test file:
      error: Browser did not start after 30000ms.

test/timeout.js:

 ❌ Failed to run test file:
      error: Browser did not start after 30000ms.

test/use.js:

 ❌ Failed to run test file:
      error: Browser did not start after 30000ms.

Chrome: |██████████████████████████████| 10/10 test files | 0 passed, 0 failed

Finished running tests in 30.4s, all tests passed! 🎉

This should have been "0 passed, 10 failed".