Send HWUI load reset hint when Choreographer registers a callback

Send a load reset hint hint to DrawFrameTask through ThreadedRenderer
from ViewRootImpl whenever Choreographer registers a callback. This
allows the PowerHAL to allocate more resources for HWUI in response to
upcoming work, helping prevent frame drop.

Bug: b/243938267
Test: manual

Change-Id: Ie2cf809cf85530af04f4d0db3407853d4da03d62