Remove unused conditionally_execute script.

Bug: 889992
Change-Id: I9a8d8f787507c7e461b8a02ad5b130389a9f876c
Reviewed-on: https://chromium-review.googlesource.com/c/1351489Reviewed-by: Ned Nguyen <nednguyen@google.com>
Commit-Queue: Garrett Beaty <gbeaty@chromium.org>
Cr-Commit-Position: refs/heads/master@{#612303}

tools/perf/conditionally_execute

-#!/usr/bin/env vpython
-# 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 argparse
-import os
-import subprocess
-import sys
-
-
-def main(args):
-  parser = argparse.ArgumentParser()
-  parser.add_argument(
-      '--gyp-condition', '-c', type=str, required=True,
-      help=('The gyp condition that acts as the switch. If the '
-            'condition is found in environment variable GYP_DEFINES, '
-            'this will execute the target script'))
-  options, script_args = parser.parse_known_args()
-
-  # Make sure that we always execute target script with python.
-  if 'python' not in script_args[0]:
-    script_args.insert(0, sys.executable)
-
-  # A typical GYP_DEFINES string looks s.t like "foo=a bar=1 baz=c". We
-  # tokenize the string before doing string matching.
-  gyp_defines = os.environ.get('GYP_DEFINES', '').split()
-  if options.gyp_condition in gyp_defines:
-    subprocess.check_call(script_args)
-  return 0
-
-
-if __name__ == '__main__':
-  main(sys.argv[1:])