VM: Remove unnecessary _Num class from runtime/lib.

runtime/vm/bootstrap_natives.h

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #ifndef VM_BOOTSTRAP_NATIVES_H_
 #define VM_BOOTSTRAP_NATIVES_H_
 
 #include "vm/native_entry.h"
 
 // bootstrap dart natives used in the core dart library.
@@ skipping 77 matching lines @@
   V(Double_equalToInteger, 2)                                                  \
   V(Double_greaterThan, 2)                                                     \
   V(Double_equal, 2)                                                           \
   V(Double_doubleFromInteger, 2)                                               \
   V(Double_round, 1)                                                           \
   V(Double_floor, 1)                                                           \
   V(Double_ceil, 1)                                                            \
   V(Double_truncate, 1)                                                        \
   V(Double_toInt, 1)                                                           \
   V(Double_parse, 3)                                                           \
+  V(Double_toString, 1)                                                        \
   V(Double_toStringAsFixed, 2)                                                 \
   V(Double_toStringAsExponential, 2)                                           \
   V(Double_toStringAsPrecision, 2)                                             \
   V(Double_flipSignBit, 1)                                                     \
   V(RegExp_factory, 4)                                                         \
   V(RegExp_getPattern, 1)                                                      \
   V(RegExp_getIsMultiLine, 1)                                                  \
   V(RegExp_getIsCaseSensitive, 1)                                              \
   V(RegExp_getGroupCount, 1)                                                   \
   V(RegExp_ExecuteMatch, 3)                                                    \
@@ skipping 237 matching lines @@
   V(LibraryPrefix_load, 1)                                                     \
   V(LibraryPrefix_invalidateDependentCode, 1)                                  \
   V(LibraryPrefix_loadError, 1)                                                \
   V(LibraryPrefix_isLoaded, 1)                                                 \
   V(UserTag_new, 2)                                                            \
   V(UserTag_label, 1)                                                          \
   V(UserTag_defaultTag, 0)                                                     \
   V(UserTag_makeCurrent, 1)                                                    \
   V(Profiler_getCurrentTag, 0)                                                 \
   V(ClassID_getID, 1)                                                          \
-  V(Num_toString, 1)                                                           \
   V(VMService_SendIsolateServiceMessage, 2)                                    \
   V(VMService_SendRootServiceMessage, 1)                                       \
   V(VMService_OnStart, 0)                                                      \
   V(VMService_OnExit, 0)                                                       \
   V(VMService_OnServerAddressChange, 1)                                        \
   V(VMService_ListenStream, 1)                                                 \
   V(VMService_CancelStream, 1)                                                 \
   V(VMService_RequestAssets, 0)                                                \
   V(VMService_DecodeAssets, 1)                                                 \
 
@@ skipping 64 matching lines @@
 #ifndef PRODUCT
   MIRRORS_BOOTSTRAP_NATIVE_LIST(DECLARE_BOOTSTRAP_NATIVE)
 #endif
 
 #undef DECLARE_BOOTSTRAP_NATIVE
 };
 
 }  // namespace dart
 
 #endif  // VM_BOOTSTRAP_NATIVES_H_