Emit only A Single Opt Remark When Inlining

Summary:
This updates the Inliner to only add a single Optimization
Remark when Inlining, rather than an Analysis Remark and an
Optimization Remark.

Fixes https://bugs.llvm.org/show_bug.cgi?id=33786

Reviewers: anemet, davidxl, chandlerc

Reviewed By: anemet

Subscribers: haicheng, fhahn, mehdi_amini, dblaikie, llvm-commits, eraman

Differential Revision: https://reviews.llvm.org/D36054

llvm-svn: 311349