[CI] Hook cli-tests up to CI

Add cli-tests to `make test`. This adds a `python3` dependency to `make
test`, but not `make check`. We could make this dependency optional by
skipping the tests if `python3` is not present.

tests/cli-tests/bin/cmp_size

@@ -1,7 +1,5 @@
 #!/bin/sh
 
-# Small utility to
-
 set -e
 
 usage()