Remove deferred bounds updates

The purpose of deferring bounds updates was to avoid flicker
in app transition to split-screen-primary.

Not really working anymore since the task bounds are updated as
long as being reparented to split-screen organized tasks.

Bug: 153579514
Test: existing test pass
Change-Id: I02fc7d680403e87dea670f4f0e4e610821818274
3 files changed