Add scsi-stress-remove to blktests

Hi,

v2:
There was a minor typo in 0001 pointed out by Omar which I fixed here. 0002 was refactored to use common/scsi_debug. I also rebased onto the top of osandov#josef changing the test from block/022 -> block/027.

From v1:
Ming Lei's scsi-stress-remove test found a bug in blkg destruction [1] where bios being created when the request_queue was being cleaned up threw a NPE in blkg association. The fix is currently being discussed in [2]. To make this test more accessible, I've ported it to blktests with Ming Lei's copyright. I've tested this in my qemu instance and verified we do not see the NPE on a fixed kernel.

Ming, please let me know if you have any objections.

[1] https://lore.kernel.org/linux-block/CACVXFVO_QXipD3cmPvpLyBYSiEcWPN_ThQ=0pO9AwLqN-Lv93w@mail.gmail.com
[2] https://lore.kernel.org/lkml/[email protected]/

This patchset is ontop of osandov#josef 98db2e11c97f.

diffstats below:

Dennis Zhou (2):
blktests: split out cgroup2 controller and file check
blktests: add Ming Lei's scsi-stress-remove

 common/cgroup       | 18 +++++++----
 tests/block/027     | 73 +++++++++++++++++++++++++++++++++++++++++++++
 tests/block/027.out |  2 ++
 3 files changed, 88 insertions(+), 5 deletions(-)
 create mode 100755 tests/block/027
 create mode 100644 tests/block/027.out

Thanks,
Dennis