Automatic merge from submit-queue

add optional env var for allowing version skew in test cmd

If you only make a change to a server component and then re-run `test-cmd` you get a skew error.  This is really annoying.  I've left the default as it was (force version match), but now also allow `ALLOW_SKEW=true hack/test-cmd.sh` to skip the check.

@eparis worth a quick bash check, but I think I got it.