We currently pause playback to prevent further progress while the
app thread runs assertion and triggers additional actions. This is
not ideal because we do not actually want to pause playback in
almost all cases where this method used.
This can be improved by keeping the playback thread blocked and only
unblock it the next time the app thread waits for the player (either
via RobolectricUtil methods or by blocking the thread itself). To
add this automatic handling, this change introduces a new util class
for the tests that can keep the list of waiting threads statically
(because the access to this logic is spread across multiple independent
classes).
PiperOrigin-RevId: 589784204
00c7a9bcbb