Support running with timeout from test runner on Windows

[llvmbot]

Bugzilla Link	21753
Version	unspecified
OS	Windows NT
Blocks	#22141
Reporter	LLVM Bugzilla Contributor
CC	@stella.stamenova

Extended Description

In order for a Windows bot to get up and running, it needs to be able to correctly detect test hangs and timeout accordingly.

The best solution for this will be to create a separate python module that will provide an abstraction for platform-specific differences that the test suite cares about. Then the test suite can import this module and just call platform.run_with_timeout(args) or something.

[stella.stamenova]

TestAttachResume hangs about half of the time. It is one of the tests that would benefit from a timeout.

[stella.stamenova]

TestThreadStepOut.py (apparently on Windows and Linux) is another one.

[stella.stamenova]

TestEvents.py also

[stella.stamenova]

TestBreakpointIgnoreCount.py and TestVirtual.py will also occasionally hang on Windows

[llvmbot]

mentioned in issue #22141