Lit: rewind WinWaitReleased() stuff in TestRunner.

Lit: rewind WinWaitReleased() stuff in TestRunner.

r145222 "lit/TestRunner.py: [Win32] Introduce WinWaitReleased(f), to wait for file handles to be released by children."
r145223 "lit/TestRunner.py: Use RemoveForce()."
r145381 "lit/TestRunner.py: Try to catch ERROR_FILE_NOT_FOUND, too."
r152916 "lit/TestRunner.py: [Win32] Check all opened_files[] released, rather than (obsoleted) written_files[]."
r153172 "lit/TestRunner.py: [Win32] Rework WinWaitReleased() again! "win32file" from Python Win32 Extensions."

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@156381 91177308-0d34-0410-b5e6-96231b3b80d8