Introduce a BuiltinsConstructStub that sets up new.target and does a [[call]] per ES6 9.3.2

src/execution.h

 // Copyright 2014 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef V8_EXECUTION_H_
 #define V8_EXECUTION_H_
 
 #include "src/allocation.h"
 #include "src/base/atomicops.h"
 #include "src/handles.h"
@@ skipping 46 matching lines @@
       Isolate* isolate, Handle<Object> obj);
 
   // ECMA-262 9.9
   MUST_USE_RESULT static MaybeHandle<Object> ToObject(
       Isolate* isolate, Handle<Object> obj);
 
   // Create a new date object from 'time'.
   MUST_USE_RESULT static MaybeHandle<Object> NewDate(
       Isolate* isolate, double time);
 
-  // Create a new regular expression object from 'pattern' and 'flags'.
-  MUST_USE_RESULT static MaybeHandle<JSRegExp> NewJSRegExp(
-      Handle<String> pattern, Handle<String> flags);
-
   static Handle<String> GetStackTraceLine(Handle<Object> recv,
                                           Handle<JSFunction> fun,
                                           Handle<Object> pos,
                                           Handle<Object> is_global);
 };
 
 
 class ExecutionAccess;
 class PostponeInterruptsScope;
 
@@ skipping 163 matching lines @@
   friend class StackLimitCheck;
   friend class PostponeInterruptsScope;
 
   DISALLOW_COPY_AND_ASSIGN(StackGuard);
 };
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_EXECUTION_H_