selftests/tc-testing: Add a test case for DRR class with TC_H_ROOT

selftests/tc-testing: Add a test case for DRR class with TC_H_ROOT

Integrate the reproduer from Mingi to TDC.

All test results:

1..4
ok 1 0385 - Create DRR with default setting
ok 2 2375 - Delete DRR with handle
ok 3 3092 - Show DRR class
ok 4 4009 - Reject creation of DRR class with classid TC_H_ROOT

Cc: Mingi Cho <mincho@theori.io>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://patch.msgid.link/20250306232355.93864-3-xiyou.wangcong@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>