Inliner::OptimizationRemark: Fix crash in clang/test/Frontend/optimization-remark.c on some hosts, including --vg.

DebugLoc in Callsite would not live after Inliner. It should be copied before Inliner.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@206459 91177308-0d34-0410-b5e6-96231b3b80d8