Fix bug in the way an Event handles a bound thread.

This just keeps the (test) Event representation in sync with
the runtime Event representation, which is modified by

  https://googleplex-android-review.git.corp.google.com/#/c/platform/frameworks/ml/+/2880348/

Bug: 63905942
Test: vts
Change-Id: I2a6de4397c5e31e35cb3d02e241dd21452c21ca6