Support testing for DNS Transport over TCP

a. Add a large payload packet (over 512 bytes) with OPT padding for sending DNS
 query over TCP.
b. Create TCP socket and TCP response handle function in dns_responder.
c. Add GetNumQueriesForProtocol(protocol) to get the number of queries on
 TCP/UDP.

Test: cd packages/modules/DnsResolver && atest
Change-Id: I7c6926502d200980a77f47a3df057f30587521f8