Objective-C. After providing a fix-it for a
cstring, converted to NSString, produce the
matching AST for it. This also required some
refactoring of the previous code. // rdar://14106083


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@197605 91177308-0d34-0410-b5e6-96231b3b80d8