Simplify LTOInternalize into UpdateLLVMCompilerUsed

It is now only doing the update to the llvm.compiler_used global.
The client has to call separately the internalization stage.
Hopefully the code is simpler to understand this way.

From: Mehdi Amini <mehdi.amini@apple.com>

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@266174 91177308-0d34-0410-b5e6-96231b3b80d8
6 files changed