Remove tools/clang/scripts/download_objdump.py

All uses have been replaced by calls to update.py --package=objdump.

Bug: 884608
Change-Id: Icb820782786a256c0a3586e8a23f62d463689afb
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1917517
Auto-Submit: Hans Wennborg <hans@chromium.org>
Commit-Queue: Reid Kleckner <rnk@chromium.org>
Reviewed-by: Reid Kleckner <rnk@chromium.org>
Cr-Commit-Position: refs/heads/master@{#715750}

tools/clang/scripts/download_objdump.py

-#!/usr/bin/env python
-# Copyright 2017 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 sys
-
-import update
-
-# TODO(hans): Remove this forwarding hack after all callers of this script have
-# been updated to call update.py instead.
-if __name__ == '__main__':
-  sys.argv = [sys.argv[0], '--package=objdump']
-  sys.exit(update.main())