qa/standalone/osd-backfill: Modify backfill tests for mclock scheduler

qa/standalone/osd-backfill: Modify backfill tests for mclock scheduler

Modified test cases:

1. osd-backfill-prio.sh:
  Set osd_op_queue = wpq for all tests since the mclock doesn't
  consider recovery priority as part of its scheduling algorithm.

2. osd-backfill-space.sh:
  Set osd_mclock_profile to high_recovery_ops and increase the wait
  for backfills timeout to 1200 secs for the following tests:
  - TEST_backfill_test_simple()
  - TEST_backfill_test_multi()
  - TEST_backfill_test_sametarget()
  - TEST_backfill_multi_partial()
  - TEST_ec_backfill_simple()
  - TEST_ec_backfill_multi()
  - SKIP_TEST_ec_backfill_multi_partial()
  - SKIP_TEST_ec_backfill_multi_partial()

3. osd-backfill-stats:
  - TEST_backfill_ec_down_all_out():
   Set osd_mclock_profile to high_recovery_ops and increase the wait
   for recovery timeout to 240 secs.

Signed-off-by: Sridhar Seshasayee <sseshasa@redhat.com>