[snapshot] Move builtins generation into mksnapshot

test/unittests/BUILD.gn

 # Copyright 2016 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.
 
 import("../../gni/v8.gni")
 
 v8_executable("unittests") {
   testonly = true
 
   sources = [
@@ skipping 165 matching lines @@
     "../..:internal_config_base",
   ]
 
   # TODO(machenbach): Translate from gyp.
   #['OS=="aix"', {
   #  'ldflags': [ '-Wl,-bbigtoc' ],
   #}],
 
   deps = [
     "../..:v8",
+    "../..:v8_builtins_generators",
     "../..:v8_libbase",
     "../..:v8_libplatform",
     "//build/config/sanitizers:deps",
     "//build/win:default_exe_manifest",
     "//testing/gmock",
     "//testing/gtest",
   ]
 
   if (v8_enable_i18n_support) {
     deps += [ "//third_party/icu" ]
   }
 
   if (is_win) {
     # This warning is benignly triggered by the U16 and U32 macros in
     # bytecode-utils.h.
     # C4309: 'static_cast': truncation of constant value
     cflags = [ "/wd4309" ]
   }
 }