Update test to not trace thread start / join

Thread start / join produce slightly non-deterministic output depending
on the thread execution order. Calls to Thread.wait and Thread.isAlive
were missing in some traces occasionally. This CL splits the tracing
into two phases so that we can avoid tracing thread start / join for
more deterministic output

Bug: 259258187
Test: art/test.py -t 2246
Change-Id: I8c34832841293bec2921190229aa0a9aa1d7ba3f
2 files changed