Macro tests thread hang

[Simn]

The macro tests sometimes hang here:

         +test-macro | Changing directory to /tests/threads
         +test-macro | Command: haxe [build.hxml,--interp]
         +test-macro | Running cases.TestEvents...
         +test-macro |     testThreadRunWithEventLoop
         +test-macro |     testRun
         +test-macro |     testRepeat
         +test-macro |     testPromisedEvents
         +test-macro |     testIssue10567_runEventsInOrderByTime
         +test-macro | Running cases.TestTimer...
         +test-macro |     testCorrectInterval
         +test-macro |     testCallbackInSameThread
         +test-macro | Running cases.TestSemaphore...
         +test-macro |     test
         +test-macro | Running cases.TestMutex...
         +test-macro |     testIssue10249
         +test-macro | Running cases.TestMainLoop...
         +test-macro |     testWorksInStaticInits_issue10114
         +test-macro |     testNewAction_immediately
         +test-macro | Running cases.TestFixedThreadPool...
         +test-macro |     testShutdown_finishesSubmittedTasks
         +test-macro |     testShutdownRun_exception
         +test-macro |     testMultipleShutdown
         +test-macro |     testCreateRunShutdown
         +test-macro | Running cases.TestElasticThreadPool...
         +test-macro |     testShutdown_finishesSubmittedTasks
         +test-macro |     testShutdownRun_exception
         +test-macro |     testMultipleShutdown
         +test-macro |     testCreateRunShutdown
         +test-macro |     testThreadTimeout
         +test-macro | Running cases.TestCondition...
         +test-macro |     test

This test was added in #10503 by @Apprentice-Alchemist. I haven't investigated this yet.