Optimize HWUI ADPF for sysui and ensure correct closure

This patch prevents the HintSessionWrapper from setting the
timestamp on load_up hints, to avoid edge cases in systemui
where load_up hints were being sent before reset had a chance
to be checked, making ADPF think work was still ongoing.

This patch also ensures the session closes when a
CanvasContext is destructed, as previously it would wait until
the delayed destroy was evaluated before closing the session.

Bug: 302620048
Test: hwuiunit
Change-Id: I15172382665934acc28c80ff06937475481ba62b