cros_compute: Add a config to aid in testing changes to cros_compute.

When testing changes to cros_compute, an image with -testing suffix is
created. A new instance is then launched with this image to sanity check
the new image.

This CL adds a config that allows us to launch an instance with the
testing image.

BUG=None.
TEST=Launched a testing instance.

Change-Id: I7e5d82f7ddb077378a250b3b6aed98ccf76a3479
Reviewed-on: https://chromium-review.googlesource.com/262266
Trybot-Ready: Prathmesh Prabhu <pprabhu@chromium.org>
Tested-by: Prathmesh Prabhu <pprabhu@chromium.org>
Reviewed-by: Fang Deng <fdeng@chromium.org>
Commit-Queue: Prathmesh Prabhu <pprabhu@chromium.org>
1 file changed