Remove some scripts that were used by the valgrind bots.

testing/scripts/run_under_valgrind.py

-#!/usr/bin/env python
-# Copyright 2016 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 json
-import os
-import sys
-
-
-import common
-
-
-def main_run(args):
-  rc = common.run_runtest(args, [
-      os.path.join(common.SRC_DIR, 'tools', 'valgrind', 'chrome_tests.sh'),
-      '--tool', 'memcheck',
-      '--build-dir', os.path.join(common.SRC_DIR, 'out', args.build_config_fs),
-    ] + args.args)
-
-  json.dump({
-      'valid': True,
-      'failures': ['failed'] if rc else []
-  }, args.output)
-
-  return rc
-
-
-def main_compile_targets(args):
-  json.dump(['$name'], args.output)
-
-
-if __name__ == '__main__':
-  funcs = {
-    'run': main_run,
-    'compile_targets': main_compile_targets,
-  }
-  sys.exit(common.run_script(sys.argv[1:], funcs))