qa/standalone/scrub: remove TEST_recovery_scrub_2

qa/standalone/scrub: remove TEST_recovery_scrub_2

That test does no longer match the actual requirements and
implementation of scrubbing.
It was already deactivated in
https://github.com/ceph/ceph/pull/59590. Here - it is
fully removed, mainly for the sake of backporting.

Fixes (original): https://tracker.ceph.com/issues/50245
Fixes (Squid backport): https://tracker.ceph.com/issues/68403

(cherry picked from commit 0c4028a6a356ae8c6e7d6d646e96c8e38a114789)
Signed-off-by: Ronen Friedman <rfriedma@redhat.com>