[autotest] change more python shebangs to python2

Make sure all these scripts run as Python 2 since there is no support
for Python 3 in this code base.  This allows us to change the default
`python` to Python 3.  This catches patterns I missed previously.

BUG=chromium:990593
TEST=CQ passes

Change-Id: I45e226d65d8a406e984e103a3687124c5d09c36b
Reviewed-on: https://chromium-review.googlesource.com/1761350
Tested-by: Mike Frysinger <vapier@chromium.org>
Commit-Ready: Mike Frysinger <vapier@chromium.org>
Legacy-Commit-Queue: Commit Bot <commit-bot@chromium.org>
Reviewed-by: Vadim Bendebury <vbendeb@chromium.org>
Reviewed-by: Allen Li <ayatane@chromium.org>
diff --git a/site_utils/abort_suite.py b/site_utils/abort_suite.py
index c461463..c57e008 100755
--- a/site_utils/abort_suite.py
+++ b/site_utils/abort_suite.py
@@ -1,4 +1,4 @@
-#!/usr/bin/python -t
+#!/usr/bin/python2 -t
 #
 # Copyright (c) 2013 The Chromium OS Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be