Reland "[builtins] migrate C++ String Iterator builtins to baseline TurboFan"

src/builtins/builtins.h

 // Copyright 2011 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_BUILTINS_BUILTINS_H_
 #define V8_BUILTINS_BUILTINS_H_
 
 #include "src/base/flags.h"
 #include "src/handles.h"
 
@@ skipping 546 matching lines @@
   /* ES6 section 21.1.3.19 String.prototype.substring ( start, end ) */       \
   TFJ(StringPrototypeSubstring, 3)                                            \
   /* ES6 section 21.1.3.25 String.prototype.toString () */                    \
   TFJ(StringPrototypeToString, 1)                                             \
   CPP(StringPrototypeTrim)                                                    \
   CPP(StringPrototypeTrimLeft)                                                \
   CPP(StringPrototypeTrimRight)                                               \
   /* ES6 section 21.1.3.28 String.prototype.valueOf () */                     \
   TFJ(StringPrototypeValueOf, 1)                                              \
   /* ES6 #sec-string.prototype-@@iterator */                                  \
-  CPP(StringPrototypeIterator)                                                \
+  TFJ(StringPrototypeIterator, 1)                                             \
                                                                               \
   /* StringIterator */                                                        \
-  CPP(StringIteratorPrototypeNext)                                            \
+  TFJ(StringIteratorPrototypeNext, 1)                                         \
                                                                               \
   /* Symbol */                                                                \
   CPP(SymbolConstructor)                                                      \
   CPP(SymbolConstructor_ConstructStub)                                        \
   /* ES6 section 19.4.3.4 Symbol.prototype [ @@toPrimitive ] ( hint ) */      \
   TFJ(SymbolPrototypeToPrimitive, 2)                                          \
   /* ES6 section 19.4.3.2 Symbol.prototype.toString ( ) */                    \
   TFJ(SymbolPrototypeToString, 1)                                             \
   /* ES6 section 19.4.3.3 Symbol.prototype.valueOf ( ) */                     \
   TFJ(SymbolPrototypeValueOf, 1)                                              \
@@ skipping 148 matching lines @@
 
   friend class Isolate;
 
   DISALLOW_COPY_AND_ASSIGN(Builtins);
 };
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_BUILTINS_BUILTINS_H_