SurfaceFlinger: Cache updateInputWindows call

This is a conservative but safe cache. We invalidate it if
any layer with InputInfo, or any layer whose children/relative-children
have input info updates their drawing state. Not all these drawing state
updates will result in Input changes, but we can be confident that
without some drawing state change there wont be any Input changes,
and thus it seems the cache is safe. This will solve the case of
moving layers that don't have any InputInfo assosciated generating
setInputWindows calls.

Bug: 148675756
Test: Existing tests pass. go/wm-smoke
Change-Id: Ie5979b25370c2d5c3d8a55f187fc6fda1cc75b27