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 = {
   "git_url": "https://chromium.googlesource.com",
 }
 
 deps = {
   "v8/build/gyp":
     Var("git_url") + "/external/gyp.git" + "@" + "0bb67471bca068996e15b56738fa4824dfa19de0",
   "v8/third_party/icu":
     Var("git_url") + "/chromium/deps/icu.git" + "@" + "f1ad7f9ba957571dc692ea3e187612c685615e19",
   "v8/buildtools":
-    Var("git_url") + "/chromium/buildtools.git" + "@" + "dc487f429cb90cac92ec7a9cd9d49db13648064d",
+    Var("git_url") + "/chromium/buildtools.git" + "@" + "a85661f97e83c620a8a1d0255829eb7a674e12cc",
   "v8/testing/gtest":
     Var("git_url") + "/external/googletest.git" + "@" + "23574bf2333f834ff665f894c97bef8a5b33a0a9",
   "v8/testing/gmock":
     Var("git_url") + "/external/googlemock.git" + "@" + "29763965ab52f24565299976b936d1265cb6a271",  # from svn revision 501
   "v8/tools/clang":
     Var("git_url") + "/chromium/src/tools/clang.git" + "@" + "dbc958e1b51949ca815ca31a8f9bf4a760ca1d35",
 }
 
 deps_os = {
   "android": {
@@ skipping 82 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/build/gyp_v8"],
   },
 ]