Re-enable llvm/test/ThinLTO/X86/cache.ll.
Re-enable llvm/test/ThinLTO/X86/cache.ll.

This reverts;
  r269548, "XFAIL ThinLTO Caching test on Windows."
  r269561, "Rework r269548, "XFAIL ThinLTO Caching test on Windows.", not to use XFAIL, for now."

git-svn-id: 0ff597fd157e6f4fc38580e8d64ab130330d2411@269567 91177308-0d34-0410-b5e6-96231b3b80d8

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