[libcxx] Implement temp_directory_path using GetTempPath on windows

This does roughly the same as the manual implementation, but checks
a slightly different set of environment variables and has a more
appropriate fallback if no environment variables are available
(/tmp isn't a very useful fallback on windows).

Differential Revision: https://reviews.llvm.org/D91175

GitOrigin-RevId: d4f4e723d0b4f09d72880f1679c02d586bf8abfa
1 file changed