improve of note message and minor refactoring of my last

include/clang/Basic/DiagnosticSemaKinds.td

lib/Sema/SemaExprObjC.cpp

test/Analysis/inlining/DynDispatchBifurcate.m

test/Analysis/rdar-6540084.m

test/Modules/objc-categories.m

test/PCH/chain-categories2.m

test/SemaObjC/call-super-2.m

test/SemaObjC/compare-qualified-id.m

test/SemaObjC/conditional-expr.m

test/SemaObjC/error-outof-scope-property-use.m

test/SemaObjC/instancetype.m

test/SemaObjC/message.m

test/SemaObjC/method-not-defined.m

test/SemaObjC/missing-atend-metadata.m

test/SemaObjC/property-5.m

test/SemaObjC/protocol-id-test-1.m

test/SemaObjCXX/instancetype.mm