Revert of Remove SIMD.js from V8.

DEPS

 # Note: The buildbots evaluate this file with CWD set to the parent
 # directory and assume that the root of the checkout is in ./v8/, so
 # all paths in here must match this assumption.
 
 vars = {
   "chromium_url": "https://chromium.googlesource.com",
 }
 
 deps = {
   "v8/build":
@@ skipping 15 matching lines @@
   "v8/tools/swarming_client":
     Var('chromium_url') + '/external/swarming.client.git' + '@' + "ebc8dab6f8b8d79ec221c94de39a921145abd404",
   "v8/testing/gtest":
     Var("chromium_url") + "/external/github.com/google/googletest.git" + "@" + "6f8a66431cb592dad629028a50b3dd418a408c87",
   "v8/testing/gmock":
     Var("chromium_url") + "/external/googlemock.git" + "@" + "0421b6f358139f02e102c9c332ce19a33faf75be",
   "v8/test/benchmarks/data":
     Var("chromium_url") + "/v8/deps/third_party/benchmarks.git" + "@" + "05d7188267b4560491ff9155c5ee13e207ecd65f",
   "v8/test/mozilla/data":
     Var("chromium_url") + "/v8/deps/third_party/mozilla-tests.git" + "@" + "f6c578a10ea707b1a8ab0b88943fe5115ce2b9be",
+  "v8/test/simdjs/data": Var("chromium_url") + "/external/github.com/tc39/ecmascript_simd.git" + "@" + "baf493985cb9ea7cdbd0d68704860a8156de9556",
   "v8/test/test262/data":
     Var("chromium_url") + "/external/github.com/tc39/test262.git" + "@" + "a72ee6d91275aa6524e84a9b7070103411ef2689",
   "v8/test/test262/harness":
     Var("chromium_url") + "/external/github.com/test262-utils/test262-harness-py.git" + "@" + "0f2acdd882c84cff43b9d60df7574a1901e2cdcd",
   "v8/tools/clang":
     Var("chromium_url") + "/chromium/src/tools/clang.git" + "@" + "404d5421df201261afb240fd562872841d3850e0",
 }
 
 deps_os = {
   "android": {
@@ skipping 242 matching lines @@
     'name': 'clang',
     'pattern': '.',
     'action': ['python', 'v8/tools/clang/scripts/update.py', '--if-needed'],
   },
   {
     # A change to a .gyp, .gypi, or to GYP itself should run the generator.
     "pattern": ".",
     "action": ["python", "v8/gypfiles/gyp_v8", "--running-as-hook"],
   },
 ]