This is along the same lines as r234832, but for `DILocation`. Clean
out all accessors from `DILocation`. Any callers should be using
`MDLocation` directly (e.g., via `operator->()`).
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@234835 91177308-0d34-0410-b5e6-96231b3b80d8