Do not export natives to runtime via js builtins object.

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/zone.h"
@@ skipping 283 matching lines @@
   F(BreakIteratorNext, 1, 1)                 \
   F(BreakIteratorCurrent, 1, 1)              \
   F(BreakIteratorBreakType, 1, 1)
 #else
 #define FOR_EACH_INTRINSIC_I18N(F)
 #endif
 
 
 #define FOR_EACH_INTRINSIC_INTERNAL(F)        \
   F(CheckIsBootstrapping, 0, 1)               \
+  F(ImportToRuntime, 1, 1)                    \
+  F(ImportExperimentalToRuntime, 1, 1)        \
   F(Throw, 1, 1)                              \
   F(ReThrow, 1, 1)                            \
   F(UnwindAndFindExceptionHandler, 0, 1)      \
   F(PromoteScheduledException, 0, 1)          \
   F(ThrowReferenceError, 1, 1)                \
   F(NewTypeError, 2, 1)                       \
   F(NewSyntaxError, 2, 1)                     \
   F(NewReferenceError, 2, 1)                  \
   F(ThrowIteratorResultNotAnObject, 1, 1)     \
   F(ThrowStrongModeImplicitConversion, 0, 1)  \
@@ skipping 820 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_