[windows] Disable clang-format download for bot failures

Change-Id: I137675fc73e4b068baf1100b684ae0d694d12977
Reviewed-on: https://dart-review.googlesource.com/4607
Reviewed-by: Zach Anderson <zra@google.com>

tools/buildtools/update.py

@@ -94,7 +94,9 @@ def main(argv):
     result = UpdateGNOnWindows()
     if result != 0:
       return result
-    return UpdateClangFormatOnWindows()
+    # TODO(zra): Re-enable clang-format download when gs is fixed for the bots.
+    # return UpdateClangFormatOnWindows()
+    return 0
   if Update() != 0:
     return 1
   return CopyClangFormat()