[F20] Removing lsb-utils, and python3 from usr/bin Also, adding a symlink to test_that BUG=b:188712077 TEST=test_that inside container. Change-Id: I7e34f6f8910c815cfe937448ccfa51fd43180022 Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/dev-util/+/2983645 Tested-by: Derek Beckett <dbeckett@chromium.org> Auto-Submit: Derek Beckett <dbeckett@chromium.org> Reviewed-by: Keith Haddow <haddowk@chromium.org> Commit-Queue: Derek Beckett <dbeckett@chromium.org>