Add more logging to 2246-trace-stream test

2246-trace-stream is failing flakily with a low frequency with a NPE.
Adding some logging to see what's going on. The parser seems to see an
event on a thread that doesn't have a corresponding log for information
about the thread.

Bug: 279547877
Test: art/test.py -t 2246
Change-Id: Id1bd3ce3c98ef382410986f5d4a0e06d82f688c0