Revert "[CMake][libcxx] Move Python check to main CMake file"

This reverts commit 39441fe9f00a58ffc2fdff92a4b0e8a280a5f444.

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@291728 91177308-0d34-0410-b5e6-96231b3b80d8
2 files changed