[GlobalMerge] Handle llvm.compiler.used correctly.

Reuse the handling for llvm.used, and don't transform such globals.

Fixes a failure on the asan buildbot caused by my previous commit.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@337973 91177308-0d34-0410-b5e6-96231b3b80d8
2 files changed