btrfs: add test case to verify the behavior with large RAID0 data chunks

btrfs: add test case to verify the behavior with large RAID0 data chunks

There is a recent regression during v6.4 merge window, that a u32 left
shift overflow can cause problems with large data chunks (over 4G
sized).

This is the regression test case for it.

The test case itself would:

- Create a RAID0 chunk with a single 6G data chunk
  This requires at least 6 devices from SCRATCH_DEV_POOL, and each
  should be larger than 2G.

- Fill the fs with 5G data

- Make sure everything is fine
  Including the data csums.

- Delete half of the data

- Do a fstrim
  This would lead to out-of-boundary trim if the kernel is not patched.

- Make sure everything is fine again
  If not patched, we may have corrupted data due to the bad fstrim
  above.

For now, this test case only checks the behavior for RAID0.
As for RAID10, we need 12 devices, which is out-of-reach for a lot of
test envionrments.

For RAID56, they would have a different test case, as they don't support
discard inside the RAID56 chunks.

Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Zorro Lang <zlang@kernel.org>