Add Builtin.ObjCPointer with accompanying IR-gen support and

wrap it in an 'id' type in the standard library.

Also fix a bug noticed by inspection where initWithTake for
function types wasn't entering a cleanup for the taken value.
This probably doesn't matter for existing possibilities, but
it's potentially important under exceptions.

Swift SVN r1902

lib/Parse/ParsePattern.cpp

@@ -29,6 +29,7 @@ bool Parser::checkFullyTyped(Type type) {
   case TypeKind::BuiltinFloat:
   case TypeKind::BuiltinRawPointer:
   case TypeKind::BuiltinObjectPointer:
+  case TypeKind::BuiltinObjCPointer:
   case TypeKind::NameAlias: // FIXME: underlying type could be non-fully-typed!
   case TypeKind::Identifier:
   case TypeKind::Protocol: