[preprocessor] When "merging" macro argument tokens into one SLocEntry chunk,
make sure they came from the same kind of FileIDs.

Thanks to Abramo Bagnara for providing the test case.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@170616 91177308-0d34-0410-b5e6-96231b3b80d8
3 files changed