Remove dead JSReceiver::SetElement method.

src/objects.h

Index: src/objects.h
diff --git a/src/objects.h b/src/objects.h
index f800c5d580eace363c14b94ac947af8cec798fc7..01d9428308c03f80931e13ec098fc57de3beaabb 100644
--- a/src/objects.h
+++ b/src/objects.h
@@ -1980,14 +1980,6 @@ class JSReceiver: public HeapObject {
                                       uint32_t index,
                                       DeleteMode mode);
 
-  // Set the index'th array element.
-  // Can cause GC, or return failure if GC is required.
-  MUST_USE_RESULT MaybeObject* SetElement(uint32_t index,
-                                          Object* value,
-                                          PropertyAttributes attributes,
-                                          StrictModeFlag strict_mode,
-                                          bool check_prototype);
-
   // Tests for the fast common case for property enumeration.
   bool IsSimpleEnum();
 
@@ -9040,11 +9032,6 @@ class JSProxy: public JSReceiver {
       Object* value,
       PropertyAttributes attributes,
       StrictModeFlag strict_mode);
-  MUST_USE_RESULT MaybeObject* SetElementWithHandler(
-      JSReceiver* receiver,
-      uint32_t index,
-      Object* value,
-      StrictModeFlag strict_mode);
 
   // If the handler defines an accessor property with a setter, invoke it.
   // If it defines an accessor property without a setter, or a data property