Animated gifs that want to reuse frames are failing to do so

Introduced by https://github.com/flutter/engine/pull/31098/files#r1128462935

Cause of b/271947267

A gif can request that you reuse a previous frame multiple times. The linked PR introduced a change where we fail to reuse the previous frame if it was not created on the last cycle.


I have a local patch that fixes this, working on a regression test now.

/cc @bdero fyi