Test: add test UseDohAsLongAsHostnameMatch

This is a test for aosp/2598287 that DnsResolver can use the
DoH servers of an allowed DoH provider even if the servers
are not listed in the DoH list.

Bug: 286969157
Test: test passed
Change-Id: I68a381b6ef57ad01300a5f5492eca794efdec785
1 file changed