Turn Array.isArray into a Turbofan stub

src/runtime/runtime-array.cc

Index: src/runtime/runtime-array.cc
diff --git a/src/runtime/runtime-array.cc b/src/runtime/runtime-array.cc
index ab436c2237ddef39a779ac04f94934c1bb739204..8315bfbc88ca781b7a22af4303764feb24d4a36e 100644
--- a/src/runtime/runtime-array.cc
+++ b/src/runtime/runtime-array.cc
@@ -455,6 +455,15 @@ RUNTIME_FUNCTION(Runtime_HasComplexElements) {
   return isolate->heap()->false_value();
 }
 
+// ES6 22.1.2.2 Array.isArray
+RUNTIME_FUNCTION(Runtime_ArrayIsArray) {
+  HandleScope shs(isolate);
+  DCHECK(args.length() == 1);
+  CONVERT_ARG_HANDLE_CHECKED(Object, object, 0);
+  Maybe<bool> result = Object::IsArray(object);
+  MAYBE_RETURN(result, isolate->heap()->exception());
+  return isolate->heap()->ToBoolean(result.FromJust());
+}
 
 RUNTIME_FUNCTION(Runtime_IsArray) {
   SealHandleScope shs(isolate);
@@ -463,7 +472,6 @@ RUNTIME_FUNCTION(Runtime_IsArray) {
   return isolate->heap()->ToBoolean(obj->IsJSArray());
 }
 
-
 RUNTIME_FUNCTION(Runtime_HasCachedArrayIndex) {
   SealHandleScope shs(isolate);
   DCHECK(args.length() == 1);