Make new PM honor -fdebug-info-for-profiling (clang side)

Summary: The new PM needs to invoke add-discriminator pass when building with -fdebug-info-for-profiling.

Reviewers: chandlerc, davidxl

Reviewed By: chandlerc

Subscribers: sanjoy, cfe-commits

Differential Revision: https://reviews.llvm.org/D35746

llvm-svn: 309282