CodeGen: switch to a range based for loop

Use a range based for loop instead of manual iteration.  NFC.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@215287 91177308-0d34-0410-b5e6-96231b3b80d8
MC: cleanup includes

Cleanup Win64EH header inclusion.  NFC.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@215288 91177308-0d34-0410-b5e6-96231b3b80d8
MC: remove duplicated code

This removes the duplicate definition of GetXDataSection.  This function is
available as a static method and is identical to the previous implementation.
This just cleans up the unnecessary duplication.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@215289 91177308-0d34-0410-b5e6-96231b3b80d8