swift234

Fix <rdar://problem/22584076> QoI: Using array literal init with dictionary produces bogus error

This includes a few changes:
 - Enhance diagnoseGeneralConversionFailure to not ignore constraints that are fully solved by
   CSDiags' heuristics.
 - Enhance dictionary/array literals diagnostics to handle non-compliance to their literal 
   protocols with a specific and custom error message.
 - Add specific QoI for turning accidental use of array literals in dictionary context into
   the right dictionary syntax (with a fixit).


Swift SVN r31696