Refactor the IL for object allocation with type arguments.

runtime/vm/intermediate_language.h

Index: runtime/vm/intermediate_language.h
===================================================================
--- runtime/vm/intermediate_language.h	(revision 22932)
+++ runtime/vm/intermediate_language.h	(working copy)
@@ -3710,18 +3710,16 @@
 };
 
 
-class AllocateObjectWithBoundsCheckInstr : public TemplateDefinition<2> {
+class AllocateObjectWithBoundsCheckInstr : public TemplateDefinition<0> {
  public:
-  AllocateObjectWithBoundsCheckInstr(ConstructorCallNode* node,
-                                     Value* type_arguments,
-                                     Value* instantiator)
+  explicit AllocateObjectWithBoundsCheckInstr(ConstructorCallNode* node)
       : ast_node_(*node) {
-    SetInputAt(0, type_arguments);
-    SetInputAt(1, instantiator);
   }
 
   DECLARE_INSTRUCTION(AllocateObjectWithBoundsCheck)
 
+  virtual intptr_t ArgumentCount() const { return 4; }
+
   const Function& constructor() const { return ast_node_.constructor(); }
   intptr_t token_pos() const { return ast_node_.token_pos(); }