Add some DoH tests in resolv_integration_test

The tests include:
[1] 1 test in TransportParameterizedTest
[2] 3 tests in PrivateDnsDohTest

Bug: 155855709
Bug: 181642979
Test: cd packages/modules/DnsResolver && atest
Change-Id: I8b5a85ad5556e7ff093656234069a81f29417c6a