cros_bundle_firmware: Add a script to build the test file

Instead of checking in the test file as a binary, create a script to
build it.

BUG=none
TEST=FEATURES=test sudo -E emerge cros-devutils

Change-Id: I47077c349b88ba934ad5d1238aa775f8b59e8679
Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-on: https://gerrit.chromium.org/gerrit/42935
Reviewed-by: Mike Frysinger <vapier@chromium.org>
1 file changed