selftests/tc-testings: add selftests for gate action

Test 5153: Add gate action with priority and sched-entry
Test 7189: Add gate action with base-time
Test a721: Add gate action with cycle-time
Test c029: Add gate action with cycle-time-ext
Test 3719: Replace gate base-time action
Test d821: Delete gate action with valid index
Test 3128: Delete gate action with invalid index
Test 7837: List gate actions
Test 9273: Flush gate actions
Test c829: Add gate action with duplicate index
Test 3043: Add gate action with invalid index
Test 2930: Add gate action with cookie

Signed-off-by: Zhengchao Shao <shaozhengchao@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>