Suppress clang-tools-extra/test/clang-tidy/clang-tidy-diff.cpp on win32 due to dos path issue.

I'll fix it later.

git-svn-id: https://llvm.org/svn/llvm-project/clang-tools-extra/trunk@211831 91177308-0d34-0410-b5e6-96231b3b80d8
Make clang-tidy-diff.py py3-compatible.

git-svn-id: https://llvm.org/svn/llvm-project/clang-tools-extra/trunk@211834 91177308-0d34-0410-b5e6-96231b3b80d8