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

src/execution.cc

 // 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.
 
 #include "src/execution.h"
 
 #include "src/bootstrapper.h"
 #include "src/codegen.h"
 #include "src/deoptimizer.h"
 #include "src/isolate-inl.h"
@@ skipping 439 matching lines @@
 MaybeHandle<Object> Execution::ToObject(Isolate* isolate, Handle<Object> obj) {
   Handle<JSReceiver> receiver;
   if (JSReceiver::ToObject(isolate, obj).ToHandle(&receiver)) {
     return receiver;
   }
   THROW_NEW_ERROR(
       isolate, NewTypeError(MessageTemplate::kUndefinedOrNullToObject), Object);
 }
 
 
-MaybeHandle<JSRegExp> Execution::NewJSRegExp(Handle<String> pattern,
-                                             Handle<String> flags) {
-  Isolate* isolate = pattern->GetIsolate();
-  Handle<JSFunction> function = Handle<JSFunction>(
-      isolate->native_context()->regexp_function());
-  Handle<Object> re_obj;
-  ASSIGN_RETURN_ON_EXCEPTION(
-      isolate, re_obj,
-      RegExpImpl::CreateRegExpLiteral(function, pattern, flags),
-      JSRegExp);
-  return Handle<JSRegExp>::cast(re_obj);
-}
-
-
 Handle<String> Execution::GetStackTraceLine(Handle<Object> recv,
                                             Handle<JSFunction> fun,
                                             Handle<Object> pos,
                                             Handle<Object> is_global) {
   Isolate* isolate = fun->GetIsolate();
   Handle<Object> args[] = { recv, fun, pos, is_global };
   MaybeHandle<Object> maybe_result =
       TryCall(isolate, isolate->get_stack_trace_line_fun(),
               isolate->factory()->undefined_value(), arraysize(args), args);
   Handle<Object> result;
@@ skipping 46 matching lines @@
 
   isolate_->counters()->stack_interrupts()->Increment();
   isolate_->counters()->runtime_profiler_ticks()->Increment();
   isolate_->runtime_profiler()->OptimizeNow();
 
   return isolate_->heap()->undefined_value();
 }
 
 }  // namespace internal
 }  // namespace v8