selftests/tc-testing: add selftests for qfq qdisc

Test 0582: Create QFQ with default setting
Test c9a3: Create QFQ with class weight setting
Test 8452: Create QFQ with class maxpkt setting
Test d920: Create QFQ with multiple class setting
Test 0548: Delete QFQ with handle
Test 5901: Show QFQ class

Signed-off-by: Zhengchao Shao <shaozhengchao@huawei.com>
Reviewed-by: Victor Nogueira <victor@mojatatu.com>
Tested-by: Victor Nogueira <victor@mojatatu.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>