Fix PrivateDnsDohTest.ExcessDnsRequests not to interfere other tests am: a4d7bb98

    for (const auto& fd : fds) {

        expectAnswersValid(fd, AF_INET6, kQueryAnswerAAAA);

    }

    EXPECT_TRUE(doh.block_sending(false));

    // There are some queries that fall back to DoT rather than UDP since the DoH client rejects

    // any new DNS requests when the capacity is full.

    // Expect two queries: one for DoH probe and the other one for kQueryHostname.

    EXPECT_EQ(doh_ipv6.queries(), 2);

    mDnsClient.TearDownOemNetwork(TEST_NETID_2);

    // The DnsResolver will reconnect to the DoH server for the query that gets blocked at

    // dispatcher sending channel. However, there's no way to know when the reconnection will start.

    // We have to periodically send a DNS request to check it. After the reconnection starts, the

    // DNS query will be sent to the Doh server instead of the cleartext DNS server. Then, we

    // are safe to end the test. Otherwise, the reconnection will interfere other tests.

    EXPECT_EQ(doh.queries(), 0);

    for (int i = 0; i < 50; i++) {

        sleep_for(milliseconds(100));

        int fd = resNetworkQuery(TEST_NETID, kQueryHostname, ns_c_in, ns_t_aaaa,

                                 ANDROID_RESOLV_NO_CACHE_LOOKUP);

        expectAnswersValid(fd, AF_INET6, kQueryAnswerAAAA);

        if (doh.queries() > 0) break;

    }

    EXPECT_GT(doh.queries(), 0);

}

// Tests the scenario where the DnsResolver runs out of QUIC connection data limit.