[Test] Fix BlockDnsQuery_FlaggedOff failures in MTS

The test fails in MTS because the fake DoT server closes SSL connection
after replying to each query. DNS resolver needs to disable
dot_async_handshake flag and have at least a dot retry. But the current
settings pushed by server can be different. Test should fix the setting.

Bug: 313401764
Test: adb shell
      setprop persist.device_config.netd_native.dot_async_handshake 0
      setprop persist.device_config.netd_native.dot_maxtries 3
      atest resolv_integration_test
Change-Id: Idb4fb3f88466b198c91bbab171f9c755a01468f4