chore(runtimes): fix test failures under macOS and Node.js 22

[TrevorBurnham]

This commit fixes test failures observed under macOS and Node.js 22 and adds a CI job to run the tests in an environment that uses both.

Problem

The test suite was experiencing critical issues on macOS with Node.js 22:

1. Test Process Hanging: Tests would hang indefinitely after reporting results due to a broken child process exit handler in ts-mocha.
2. Resource Leaks: Some tests weren't properly disposing of LSP connections, contributing to hanging issues.
3. Platform-Specific Failures: The webworker test was failing due to proxyquire incompatibility with Node.js 22's ES module handling.

Solution

1. Test Runner Replacement

• Replaced ts-mocha with direct mocha + ts-node/register + --exit flag
• Eliminates the problematic child process handling in ts-mocha
• Ensures clean process termination while maintaining identical functionality

2. Resource Cleanup Improvements

• Auth Tests: Added proper afterEach cleanup to dispose LSP connections

3. Node.js 22 Compatibility

• Webworker Tests: Replaced proxyquire (incompatible with Node.js 22 ES modules) with direct sinon stubbing

License

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.