swift234

Form TypeExprs for parenthesized types and another form of ? type,
allowing us to parse things like var e = (UnsafePointer<Int>[])[]() and
var c = (Int?)() 

I wouldn't be surprised if there are more type forms that should be handled,
but this gets us far enough along to consider this general area workable,
finishing off:
<rdar://problem/15295763> default constructing an optional fails to typecheck
<rdar://problem/15588967> Array type sugar default construction syntax doesn't work

If there are more type forms that are unhandled, they should be treated as
follow-on bugs.



Swift SVN r17074