Constify more uses of ASTContext&. No functional change.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@188991 91177308-0d34-0410-b5e6-96231b3b80d8
Analysis: Make %I in printf more reasonable, add more tests


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@188992 91177308-0d34-0410-b5e6-96231b3b80d8