Fix some ZFS Test Suite issues

* Add 'zfs bookmark' coverage (zfs_bookmark_cliargs)

 * Add OpenZFS 8166 coverage (zpool_scrub_offline_device)

 * Fix "busy" zfs_mount_remount failures

 * Fix bootfs_003_pos, bootfs_004_neg, zdb_005_pos local cleanup

 * Update usage of $KEEP variable, add get_all_pools() function

 * Enable history_008_pos and rsend_019_pos (non-32bit builders)

 * Enable zfs_copies_005_neg, update local cleanup

 * Fix zfs_send_007_pos (large_dnode + OpenZFS 8199)

 * Fix rollback_003_pos (use dataset name, not mountpoint, to unmount)

 * Update default_raidz_setup() to work properly with more than 3 disks

 * Use $TEST_BASE_DIR instead of hardcoded (/var)/tmp for file VDEVs

 * Update usage of /dev/random to /dev/urandom

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: loli10K <ezomori.nozomu@gmail.com>
Issue #6086 
Closes #5658 
Closes #6143 
Closes #6421 
Closes #6627 
Closes #6632

tests/runfiles/linux.run

@@ -70,6 +70,9 @@ post =
 [tests/functional/cli_root/zfs]
 tests = ['zfs_001_neg', 'zfs_002_pos', 'zfs_003_neg']
 
+[tests/functional/cli_root/zfs_bookmark]
+tests = ['zfs_bookmark_cliargs']
+
 [tests/functional/cli_root/zfs_change-key]
 tests = ['zfs_change-key', 'zfs_change-key_child', 'zfs_change-key_format',
     'zfs_change-key_inherit', 'zfs_change-key_load', 'zfs_change-key_location',
@@ -293,12 +296,10 @@ tests = ['zpool_replace_001_neg', 'replace-o_ashift', 'replace_prop_ashift']
 [tests/functional/cli_root/zpool_scrub]
 tests = ['zpool_scrub_001_neg', 'zpool_scrub_002_pos', 'zpool_scrub_003_pos',
     'zpool_scrub_004_pos', 'zpool_scrub_005_pos',
-    'zpool_scrub_encrypted_unloaded']
+    'zpool_scrub_encrypted_unloaded', 'zpool_scrub_offline_device']
 
 [tests/functional/cli_root/zpool_set]
 tests = ['zpool_set_001_pos', 'zpool_set_002_neg', 'zpool_set_003_neg']
-pre =
-post =
 
 [tests/functional/cli_root/zpool_status]
 tests = ['zpool_status_001_pos', 'zpool_status_002_pos','zpool_status_003_pos',