Do not use js builtins object to determine whether a function is a builtin.

src/runtime/runtime.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_RUNTIME_RUNTIME_H_
 #define V8_RUNTIME_RUNTIME_H_
 
 #include "src/allocation.h"
 #include "src/objects.h"
 #include "src/unicode.h"
@@ skipping 218 matching lines @@
   F(FunctionIsConciseMethod, 1, 1)                          \
   F(FunctionRemovePrototype, 1, 1)                          \
   F(FunctionGetScript, 1, 1)                                \
   F(FunctionGetSourceCode, 1, 1)                            \
   F(FunctionGetScriptSourcePosition, 1, 1)                  \
   F(FunctionGetPositionForOffset, 2, 1)                     \
   F(FunctionSetInstanceClassName, 2, 1)                     \
   F(FunctionSetLength, 2, 1)                                \
   F(FunctionSetPrototype, 2, 1)                             \
   F(FunctionIsAPIFunction, 1, 1)                            \
-  F(FunctionIsBuiltin, 1, 1)                                \
+  F(FunctionHidesSource, 1, 1)                              \
   F(SetCode, 2, 1)                                          \
   F(SetNativeFlag, 1, 1)                                    \
   F(ThrowStrongModeTooFewArguments, 0, 1)                   \
   F(IsConstructor, 1, 1)                                    \
   F(SetForceInlineFlag, 1, 1)                               \
   F(FunctionBindArguments, 4, 1)                            \
   F(BoundFunctionGetBindings, 1, 1)                         \
   F(NewObjectFromBound, 1, 1)                               \
   F(Call, -1 /* >= 2 */, 1)                                 \
   F(Apply, 5, 1)                                            \
@@ skipping 888 matching lines @@
 inline bool Runtime::AtomicIsLockFree(uint32_t size) {
   return size == 1 || size == 2 || size == 4;
 }
 
 #endif
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_RUNTIME_RUNTIME_H_