selftests/tc-testings: add selftests for ctinfo action

Test c826: Add ctinfo action with default setting
Test 0286: Add ctinfo action with dscp
Test 4938: Add ctinfo action with valid cpmark and zone
Test 7593: Add ctinfo action with drop control
Test 2961: Replace ctinfo action zone and action control
Test e567: Delete ctinfo action with valid index
Test 6a91: Delete ctinfo action with invalid index
Test 5232: List ctinfo actions
Test 7702: Flush ctinfo actions
Test 3201: Add ctinfo action with duplicate index
Test 8295: Add ctinfo action with invalid index
Test 3964: Replace ctinfo action with invalid goto_chain control

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