[Android] Log uncaught Java exceptions when running native tests.
Currently, Java exceptions hit while running native tests -- e.g. on JNI link
failure -- are lost to the logcat. This surfaces them to the test runner's
stdout.
BUG=
Committed:
https://crrev.com/6cdb933c8d2c4cadbf842fbb3ceb9cecd0f70920
Cr-Commit-Position: refs/heads/master@{#393921}