Updated the wording of two attribute-related diagnostics so that they print the offending attribute name. Also updates the associated test cases.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@198355 91177308-0d34-0410-b5e6-96231b3b80d8
Removing some manual quotes from this diagnostic, since the AST diagnostics engine knows how to handle NamedDecl objects.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@198365 91177308-0d34-0410-b5e6-96231b3b80d8
ObjectiveC. Remove false positive warning for missing property
backing ivar by not issuing this warning if ivar is referenced
somewhere and accessor makes method calls. // rdar://15727325


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@198367 91177308-0d34-0410-b5e6-96231b3b80d8
Reworded the NSObject attribute diagnostics to be more consistent with other attribute diagnostics. Also updated the associated test case.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@198368 91177308-0d34-0410-b5e6-96231b3b80d8