swift234

Eliminate the "global" list of unresolved identifier types maintained
by TranslationUnit.  This list existed solely to allow name lookup of
an unbound IdentifierType to know its DeclContext.  Instead of indirecting
through this list, just store the DeclContext in the IdentifierType in its
uninitialized state.

This eliminates a really terrible performance fixme about scanning the list,
eliminates the management fiddling around with this list in the parser, and
is generally much cleaner.


Swift SVN r5246