Remove all local variables from X86SelectionDAGInfo, the DAG has
all of the ones we were stashing away on startup.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@210385 91177308-0d34-0410-b5e6-96231b3b80d8
Replace the use of TargetMachine with a tiny bool variable.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@210386 91177308-0d34-0410-b5e6-96231b3b80d8