Add MEGAMORPHIC state support for KeyedLoadIC

src/code-stubs-hydrogen.cc

Index: src/code-stubs-hydrogen.cc
diff --git a/src/code-stubs-hydrogen.cc b/src/code-stubs-hydrogen.cc
index 83a994b1c31c5c16f68854f01016b2923b586dc9..0b98da073ce9564f397aafff514d118ec061f796 100644
--- a/src/code-stubs-hydrogen.cc
+++ b/src/code-stubs-hydrogen.cc
@@ -2176,7 +2176,7 @@ HValue* CodeStubGraphBuilder<VectorKeyedLoadStub>::BuildCodeStub() {
     generic_checker.Then();
     {
       // Tail-call to the generic KeyedLoadIC, treating it like a handler.
-      Handle<Code> stub = KeyedLoadIC::generic_stub(isolate());
+      Handle<Code> stub = KeyedLoadIC::megamorphic_stub(isolate());
       HValue* constant_stub = Add<HConstant>(stub);
       LoadDescriptor descriptor(isolate());
       HValue* op_vals[] = {context(), receiver, name};