Remove some dead code. (DarwinGDBCompat was retired in r189903).

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@192731 91177308-0d34-0410-b5e6-96231b3b80d8
Fixing some host==target assumptions in RuntimeDyld

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@192732 91177308-0d34-0410-b5e6-96231b3b80d8