Stop postponing instantiation of Type and remove InstantiatedType VM class.

runtime/vm/raw_object.cc

Index: runtime/vm/raw_object.cc
===================================================================
--- runtime/vm/raw_object.cc	(revision 7388)
+++ runtime/vm/raw_object.cc	(working copy)
@@ -340,13 +340,6 @@
 }
 
 
-intptr_t RawInstantiatedType::VisitInstantiatedTypePointers(
-    RawInstantiatedType* raw_obj, ObjectPointerVisitor* visitor) {
-  visitor->VisitPointers(raw_obj->from(), raw_obj->to());
-  return InstantiatedType::InstanceSize();
-}
-
-
 intptr_t RawAbstractTypeArguments::VisitAbstractTypeArgumentsPointers(
     RawAbstractTypeArguments* raw_obj, ObjectPointerVisitor* visitor) {
   // RawAbstractTypeArguments is an abstract class.