Skip computing proc states during app initialization

Now that app initialization covers class loading, there can be
hundreds of milliseconds delay before a top app activity gets
scheduled to start. During this delay, computing proc states
overrides the top app special case set at attachApplication to
boost the sched group.

This is fixed with the following changes:
1. Skip computing proc states when the application hasn't finished
attach application
2. Trigger a proc state update immediately after scheduling
bindApplication. This ensures that the special cased proc state is
applied as soon as possible

Test: atest MockingOomAdjusterTests
Bug: 253908737
Change-Id: Iae30a508b8b079dc88d6d5ffa027b7d805fec9e4