Revert of Remove SIMD.js from V8.

BUILD.gn

 # Copyright 2014 The Chromium 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("//build/config/android/config.gni")
 import("//build/config/arm.gni")
 import("//build/config/dcheck_always_on.gni")
 import("//build/config/mips.gni")
 import("//build/config/sanitizers/sanitizers.gni")
 
@@ skipping 469 matching lines @@
   # changes.
   inputs = [
     "tools/jsmin.py",
   ]
 
   # NOSORT
   sources = [
     "src/js/macros.py",
     "src/messages.h",
     "src/js/harmony-atomics.js",
+    "src/js/harmony-simd.js",
   ]
 
   outputs = [
     "$target_gen_dir/experimental-libraries.cc",
   ]
 
   if (v8_enable_i18n_support) {
     sources += [
       "src/js/datetime-format-to-parts.js",
       "src/js/icu-case-mapping.js",
@@ skipping 1203 matching lines @@
     "src/runtime/runtime-liveedit.cc",
     "src/runtime/runtime-maths.cc",
     "src/runtime/runtime-module.cc",
     "src/runtime/runtime-numbers.cc",
     "src/runtime/runtime-object.cc",
     "src/runtime/runtime-operators.cc",
     "src/runtime/runtime-promise.cc",
     "src/runtime/runtime-proxy.cc",
     "src/runtime/runtime-regexp.cc",
     "src/runtime/runtime-scopes.cc",
+    "src/runtime/runtime-simd.cc",
     "src/runtime/runtime-strings.cc",
     "src/runtime/runtime-symbol.cc",
     "src/runtime/runtime-test.cc",
     "src/runtime/runtime-typedarray.cc",
     "src/runtime/runtime-utils.h",
     "src/runtime/runtime-wasm.cc",
     "src/runtime/runtime.cc",
     "src/runtime/runtime.h",
     "src/safepoint-table.cc",
     "src/safepoint-table.h",
@@ skipping 1365 matching lines @@
   ]
 
   configs = [
     ":external_config",
     ":internal_config_base",
   ]
 }
 
 v8_fuzzer("wasm_data_section_fuzzer") {
 }