Fix some cases were ArrayRefs were being passed by reference. Also remove 'const' from some other ArrayRef uses since its implicitly const already.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@216524 91177308-0d34-0410-b5e6-96231b3b80d8
Simplify creation of a bunch of ArrayRefs by using None, makeArrayRef or just letting them be implicitly created.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@216525 91177308-0d34-0410-b5e6-96231b3b80d8