Refactor integration tests which using c-ares as DNS resolver

*Title*: Refactor integration tests which using c-ares as DNS resolver

*Description*:
Right now there are a lot of integration tests are using c-ares DNS resolver. For example, some tests in below files:
1) test/integration/protocol/protocol_integration_test.cc
2) test/extensions/filter/http/dynamic_forward_proxy/proxy_filter_integration_test.cc
3)test/extensions/filters/network/sni_dynamic_forward_proxy/proxy_filter_integration_test.cc
4) test/extensions/filters/http/ext_authz/ext_authz_integration_test.cc
...

The idea is to
1) Replace c-ares DNS resolver with getAddrInfo DNS resolver in those tests.
2) Add several tests in test/extensions/network/dns_resolver/cares/dns_impl_integration_test.cc to cover c-ares integration tests.