Fix flaky test ThreadStartTest

We may receive THREAD_START events for runtime internal threads (like
GCDaemon) before receiving one for the tested thread.

We now loop until receiving a THREAD_START event for the tested
thread. If we receive a THREAD_START event for another thread, we
just ignore it and wait for the next event.

Bug: 19438651
(cherry picked from commit 2d5d534cf8b1e4788317678df2301227c16e0433)

Change-Id: I6b12ef318ecb779cf9fec66b28c495b34604a668
1 file changed