swift234

fix <rdar://problem/19086357> SILGen crashes reabstracting default argument closure in members

When emitting default arguments for a parameter, emitApplyOfDefaultArgGenerator
was trying to reconstruct the original type by looking at the decl that it came
from.  However, it doesn't know the number of curry levels already applied, so it
was wrong in the case of default arguments on methods and initializers (which already
have self applied).

Fix this by having the caller pass this information in, since it knows the original
type.

While we're at it, remove the code for handling default arguments from the general 
SILGenExpr logic.  Default arguments in tuples are no longer a general thing, they 
are only valid in argument lists.



Swift SVN r27800