Update V8 DEPS.

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":
     Var("chromium_url") + "/chromium/src/build.git" + "@" + "29ac3ae139551d342de8a95f4641157d0153fc33",
   "v8/tools/gyp":
     Var("chromium_url") + "/external/gyp.git" + "@" + "e7079f0e0e14108ab0dba58728ff219637458563",
   "v8/third_party/icu":
     Var("chromium_url") + "/chromium/deps/icu.git" + "@" + "9cd2828740572ba6f694b9365236a8356fd06147",
   "v8/third_party/instrumented_libraries":
     Var("chromium_url") + "/chromium/src/third_party/instrumented_libraries.git" + "@" + "45f5814b1543e41ea0be54c771e3840ea52cca4a",
   "v8/buildtools":
-    Var("chromium_url") + "/chromium/buildtools.git" + "@" + "55ad626b08ef971fd82a62b7abb325359542952b",
+    Var("chromium_url") + "/chromium/buildtools.git" + "@" + "0ef801087682b271e9ace93cfa93e9d3dea98079",
   "v8/base/trace_event/common":
     Var("chromium_url") + "/chromium/src/base/trace_event/common.git" + "@" + "06294c8a4a6f744ef284cd63cfe54dbf61eea290",
   "v8/third_party/jinja2":
     Var("chromium_url") + "/chromium/src/third_party/jinja2.git" + "@" + "b61a2c009a579593a259c1b300e0ad02bf48fd78",
   "v8/third_party/markupsafe":
     Var("chromium_url") + "/chromium/src/third_party/markupsafe.git" + "@" + "484a5661041cac13bfc688a26ec5434b05d18961",
   "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",
@@ skipping 259 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"],
   },
 ]