Only create arguments-maps in the bootstrapper, remove now obsolete ValueType flag.

src/heap.h

Index: src/heap.h
diff --git a/src/heap.h b/src/heap.h
index 754b5588e05f89b11c8fffc7d77df82d5d29872a..720025b3cbddccae7932a8425492c2ae3b2f5c7c 100644
--- a/src/heap.h
+++ b/src/heap.h
@@ -1467,10 +1467,6 @@ class Heap {
       int length,
       PretenureFlag pretenure = NOT_TENURED);
 
-  // Allocates an arguments object - optionally with an elements array.
-  MUST_USE_RESULT AllocationResult AllocateArgumentsObject(
-      Object* callee, int length);
-
   // Copy the code and scope info part of the code object, but insert
   // the provided data as the relocation information.
   MUST_USE_RESULT AllocationResult CopyCode(Code* code,