Fix a bug I noticed. Varargs were broken if preceded by tuple parameters.

tests/mini/tuple_and_vararg.d

@@ -0,0 +1,13 @@
+// Based on dstress.run.t.tuple_15_A;
+
+module tuple_and_vararg;
+
+template TypeTuple(TList...){
+	alias TList TypeTuple;
+}
+
+void main(){
+	auto y = function(TypeTuple!(uint,uint) ab, ...){};
+        y(1, 2);
+        y(1, 2, "foo", 3.0);
+}