Convert StringLiteralParser constructor to use ArrayRef instead of a pointer and count.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@211763 91177308-0d34-0410-b5e6-96231b3b80d8
Convert some function arguments to use ArrayRef.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@211764 91177308-0d34-0410-b5e6-96231b3b80d8