onDidClasspathUpdate failing intermittently

In test/standard-mode-suite/publicApi.test.ts. Also discussed during our migration in https://github.com/redhat-developer/vscode-java/pull/2031

1) Public APIs - Standard
       onDidClasspathUpdate should work:
     Error: Timeout of 60000ms exceeded. For async tests and hooks, ensure "done()" is called; if returning a Promise, ensure it resolves. (/home/runner/work/vscode-java/vscode-java/out/test/standard-mode-suite/publicApi.test.js)
  	at listOnTimeout (internal/timers.js:554:17)
  	at processTimers (internal/timers.js:497:7)

I don't think it's strictly related to how fast the builder is, because I can't reproduce locally consistently by just limiting the process to 10% of CPU but I get the impression it happens on weaker builders under Github Actions. We had similar issues in https://github.com/redhat-developer/vscode-quarkus/issues/379 and increasing the timeouts worked, but I wonder if something else is happening here.

Start with test/standard-mode-suite/publicApi.test.ts and reproduce the intermittent onDidClasspathUpdate timeout shown in the issue. Review the migration discussion in pull request 2031 and the related vscode-quarkus issue 379, then identify whether the failure needs a timeout change or another fix; done means the test completes reliably in GitHub Actions.