Refine system bar position restoring

The previous logic restores the system bar as long as its insets source
is visible. There can be a timing issue that if the user swipes to show
transient bars while an immersive app just becomes the control target
but the hide-bar info haven't sent to WM yet, WM will re-show the bar
incorrectly.

This CL uses the requested visibility and the behavior to decide if we
should restore the postion and the visibility.

This CL also refines and caches the arguments of showTransient. In this
way, we don't have to create the array every time while invoking that
method.

Fix: 161247175
Test: atest InsetsPolicyTest
Merged-In: Idef314dfe6625399b88b3dacb4c74c7071453497
Change-Id: Idef314dfe6625399b88b3dacb4c74c7071453497