Display in-memory icon for app close while AdaptiveIcon loads.

- We already display the BubbleTextView icon during app close
  since we need the shadows to ensure a clean handoff.
- Previously, we waited until the icon and the AdaptiveIcon were
  both loaded to show the FloatingIconView.
- This change immediately shows the BubbleTextView icon so that
  we can have something displayed in the cases where AdaptiveIcon
  is slow to load (ie. immediately after killing/restarting launcher).

Currently there are cases where we defer some BubbleTextView drawing to
ClipIconView. We can refactor in master so that ClipIconView is only used
when drawable is an AdaptiveIcon.

Bug: 207389002
Test: manual
Change-Id: Ie54642fef4258862a155ab0aba6e49cea9c9ead0