netlink_listener_test tests the socket destroy listener, so it makes
sense to just merge it into the TrafficControllerTest.
Test: atest traffic_controller_unit_test
Change-Id: Ibc0b483203150aa2d7898a761fa4715dce6f4218
Delete tagSocket(), privilegedTagSocket() and untagSocket() revelant
test cases since thay are moved out of TrafficController in
aosp/1849156.
Bug: 202086915
Test: atest traffic_controller_unit_test passed
Change-Id: I605577ee4d7076f0c8ad75888a4d32bff90f6104
Delete tagSocket(), privilegedTagSocket() and untagSocket() since
they are moved out of TrafficController in aosp/1849156.
Test: m
Change-Id: I6162c758446f597eb79734e00348dc8b1fe2d422