qa/standalone: Add missing teardowns to a subset of osd-scrub-repair tests

qa/standalone: Add missing teardowns to a subset of osd-scrub-repair tests

Tests identified with missing teardown within osd-scrub-repair.sh:
  1. TEST_periodic_scrub_replicated()
  2. TEST_scrub_warning()
  3. TEST_request_scrub_priority()

Centralize setup and teardown within the run() function for all the tests.

Fixes: https://tracker.ceph.com/issues/51580
Signed-off-by: Sridhar Seshasayee <sseshasa@redhat.com>
(cherry picked from commit 84cab65e3aafcf656b860abd72a09799458f6bc5)

 Conflicts:
	qa/standalone/scrub/osd-scrub-repair.sh
 - Removed non-existent test TEST_auto_repair_bluestore_tag() and its
   associated helper functions initiate_and_fetch_state() and
   wait_end_of_scrub()