This patch simplifies a test that checks only used module map files are reported as input files in PCM files.

Instead of using opaque `diff`, this patch uses `clang -module-file-info` and `FileCheck` to verify this.

Reviewed By: dexonsmith

Differential Revision: https://reviews.llvm.org/D120463

Problem:
PCM file includes references to all module maps used in compilation which created PCM. This problem leads to PCM-rebuilds in distributed compilations as some module maps could be missing in isolated compilation. (For example in our distributed build system we create a temp folder for every compilation with only modules and headers that are needed for that particular command).

Solution:
Add only affecting module map files to a PCM-file.

Reviewed By: rsmith

Differential Revision: https://reviews.llvm.org/D106876