Add path.normalize()

--HG--
extra : rebase_source : ed7fcb25a7a0801cb812fb7508eade3349b73f37
- Expose the matching logic used by os.matchdirs() and os.matchfiles()  for overriding
- Cache results of os.is64bit()

--HG--
extra : rebase_source : 0ea8370ee82abc074912f39a44bea72dc85273c6