btrfs: fix ulist leaks in error paths of qgroup self tests

btrfs: fix ulist leaks in error paths of qgroup self tests

[ Upstream commit 7e94333f2238e3e49829f304e0381c35061b1cbf ]

In the test_no_shared_qgroup() and test_multiple_refs() qgroup self tests,
if we fail to add the tree ref, remove the extent item or remove the
extent ref, we are returning from the test function without freeing the
"old_roots" ulist that was allocated by the previous calls to
btrfs_find_all_roots(). Fix that by calling ulist_free() before returning.

Fixes: ead7e1afe481 ("btrfs: qgroup: Switch self test to extent-oriented qgroup mechanism.")
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>