[SemaObjC] Improve ObjCDictionaryLiteral and ObjCArryLiteral diagnostics

Sema actions on ObjCDictionaryLiteral and ObjCArryLiteral are currently
done as a side-effect of Sema upon parent expressions, which incurs of
delayed typo corrections for such literals to be performed by TypoTransforms
upon the ObjCDictionaryLiteral and ObjCArryLiteral themselves instead of
its elements individually.

This is specially bad because it was not designed to act on several
elements; searching through all possible combinations of corrections for
several elements is very expensive. Additionally, when one of the
elements has no correction candidate, we still explore all options and
at the end emit no typo corrections whatsoever.

Do the proper sema actions by acting on each element alone during appropriate
literal parsing time to get proper diagonistics and decent compile time
behavior.

Differential Revision: http://reviews.llvm.org/D22183

rdar://problem/21046678

llvm-svn: 276020