[libclang] Make sure to use the raw module format for libclang parsing.

Fixes crash when passing '-gmodules' in the compiler options.
rdar://23588717

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@253645 91177308-0d34-0410-b5e6-96231b3b80d8
7 files changed