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

src/regexp/jsregexp.h

 // Copyright 2012 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_REGEXP_JSREGEXP_H_
 #define V8_REGEXP_JSREGEXP_H_
 
 #include "src/allocation.h"
 #include "src/assembler.h"
 
@@ skipping 11 matching lines @@
  public:
   // Whether V8 is compiled with native regexp support or not.
   static bool UsesNativeRegExp() {
 #ifdef V8_INTERPRETED_REGEXP
     return false;
 #else
     return true;
 #endif
   }
 
-  // Creates a regular expression literal in the old space.
-  // This function calls the garbage collector if necessary.
-  MUST_USE_RESULT static MaybeHandle<Object> CreateRegExpLiteral(
-      Handle<JSFunction> constructor,
-      Handle<String> pattern,
-      Handle<String> flags);
-
   // Returns a string representation of a regular expression.
   // Implements RegExp.prototype.toString, see ECMA-262 section 15.10.6.4.
   // This function calls the garbage collector if necessary.
   static Handle<String> ToString(Handle<Object> value);
 
   // Parses the RegExp pattern and prepares the JSRegExp object with
   // generic data and choice of implementation - as well as what
   // the implementation wants to store in the data field.
   // Returns false if compilation fails.
   MUST_USE_RESULT static MaybeHandle<Object> Compile(Handle<JSRegExp> re,
@@ skipping 1636 matching lines @@
   static const int kStringOffset = 0;
   static const int kPatternOffset = 1;
   static const int kArrayOffset = 2;
   static const int kLastMatchOffset = 3;
 };
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_REGEXP_JSREGEXP_H_