Fix a regression where ':' in CPLUS_INCLUDE_PATH and friends would no longer separate paths.

This regressed in r152583. Also add a test to make sure it doesn't regress again.



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@153034 91177308-0d34-0410-b5e6-96231b3b80d8
2 files changed