swift234

similar to the previous patch, have all NominalTypeDecls auto-reparent
all of their generic parameters.  This simplifies logic creating them,
allowing us to eliminate all setDeclContext() calls from the parser.

While we're at it, change Parser::addVarsToScope to be a static 
function in ParseStmt.cpp and dramatically cut it down since none of
its remaining clients are using most of its capabilities.  It needs
to be simplified even further.


Swift SVN r13702