twister: add a wrapper script with old name

Add a simpel wrapper script called 'sanitycheck' to be removed after
Zephyr 2.5.

This script has a warning and a 5 sec delay to get the attention of the
caller.

Signed-off-by: Anas Nashif <anas.nashif@intel.com>

scripts/sanitycheck

@@ -0,0 +1,16 @@
+#!/bin/bash
+# Copyright (c) 2020 Intel Corporation
+# SPDX-License-Identifier: GPL-2.0
+#
+
+
+echo "!!!!!! WARNING !!!!!!!!"
+echo
+echo "The sanitycheck script was renamed to twister. Please call twister with same options instead."
+echo "This wrapper script will be removed after Zephyr 2.5 is released."
+echo
+echo "Sleeping for 5 seconds to get your attention..."
+sleep 5
+d=$(dirname $0)
+${d}/twister $@
+