Update getMergedLocation to check the instruction type and merge properly.

Summary: If the merged instruction is call instruction, we need to set the scope to the closes common scope between 2 locations, otherwise it will cause trouble when the call is getting inlined.

Reviewers: dblaikie, aprantl

Reviewed By: dblaikie, aprantl

Subscribers: llvm-commits, sanjoy

Differential Revision: https://reviews.llvm.org/D37877

llvm-svn: 314694