Extend ResolverTest.BrokenEdns to cover using EDNS0 for cleartext DNS

In opportunistic mode, if the resolver somehow fallbacks to cleartext
DNS servers, it uses EDNS0 to send queries. If the server can't
recognize EDNS0, the resolver retries without EDNS0 only when the
server can make a response with rcode FORMERR.

Add more testcases for ResolverTest.BrokenEdns to ensure the behavior
"retries without EDNS0 when receiving rcode FORMERR" correct.

Bug: 120257033
Test: resolv_integration_test passed
Change-Id: I373fc134a56abc12dc3ff24b3cd144c9a37f4844