ZTS: fix removal_condense_export test case

It's been observed in the CI that the required 25% of obsolete bytes
in the mapping can be to high a threshold for this test resulting in
condensing never being triggered and a test failure.  To prevent these
failures make the existing zfs_condense_indirect_obsolete_pct tuning
available so the obsolete percentage can be reduced from 25% to 5%
during this test.

Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Reviewed-by: George Melikov <mail@gmelikov.ru>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #11869

tests/test-runner/bin/zts-report.py.in

@@ -263,7 +263,6 @@ if sys.platform.startswith('freebsd'):
         'delegate/zfs_allow_003_pos': ['FAIL', known_reason],
         'inheritance/inherit_001_pos': ['FAIL', '11829'],
         'pool_checkpoint/checkpoint_zhack_feat': ['FAIL', '11854'],
-        'removal/removal_condense_export': ['FAIL', known_reason],
         'resilver/resilver_restart_001': ['FAIL', known_reason],
         'zvol/zvol_misc/zvol_misc_volmode': ['FAIL', known_reason],
     })