swift234

Consolidate list parsing and error recovery boilerplate

Fix array/dictionary literal parsing robustness by consolidating and improving
the parsing of lists in general (tuples/array/dictionary literals, attribute
lists, statement lists, declaration lists, etc).

Missing commas in tuple/array/dictionary literals or declaration attributes
are now detected, reported, and recovered from.

Premature ellipsis in tuples are now detected, reported, and recovered from.

Swift SVN r4631