Test: Don't let MultinetworkApiTest throw more than one JNI exception

This change fixes the test crash that is caused by ART's JNI failure.
ART's JNI doesn't allow native code to raise another exception while
an exception is pending.

Bug: 282896580
Test: turned off private DNS; used iptables to drop DNS packets;
      ran MultinetworkApiTest; verified no crash happened
Change-Id: Ide9e122f74d9939ce386d07d948a4e487870024f
1 file changed