move test suite out of theories/ so it does not get installed; also check output of test suite so that we can test printing

This reverts commit 913059d2.

This reverts commit 849abb8d, reversing changes
made to 8de0b894.  The merge was done
accidentally, before review happened.

I saw no need for `stuckness_flip`: strong atomicity always works,
while weak atomicity works only for expressions that are not stuck.
Since this seemed unclear, I split lemma `wp_atomic'` up into
`wp_strong_atomic` (parametric in the WP's `s`) and `wp_weak_atomic`
(not). The proof mode instance is stated in terms of the derived rule
`wp_atomic` (parametric in `s`).

Rename `UCMRA` → `Ucmra`
Rename `CMRA` → `Cmra`
Rename `OFE` → `Ofe` (`Ofe` was already used partially, but many occurences were missing)
Rename `STS` → `Sts`
Rename `DRA` → `Dra`

For obsolete reasons, that no longer seem to apply, we used ∅ as the
unit.