Fix one test for changed opt remarks format

Summary:
Optimization remark format is slightly changed by LLVM patch D49412.
One test is fixed with expected messages changed.
Frankly speaking I have not tested this change yet. I will test when manage to setup the project.

Reviewers: xbolva00, espindola

Reviewed By: xbolva00

Subscribers: emaste, arichardson, steven_wu, dexonsmith

Differential Revision: https://reviews.llvm.org/D50242

llvm-svn: 338970