RFR: 8356320: GifImageDecoder can produce wrong image when GCE changes transparent pixel index

[Jeremy Wood]

When a gif frame's disposal code is DISPOSAL_BGCOLOR and we're maintaining a saved image: we have to flood-fill the frame's bounds. And if the transparent pixel index changes across frames: we could sometimes flood fill the wrong value, resulting in an opaque rectangle in the output image.

(I know this looks similar to https://github.com/openjdk/jdk/pull/25044 , but if you look at the data structure of the sample gifs: they are separate problems with separate solutions.)

-------------

Commit messages:
 - 8356137: updating (c) year
 - 8356320: adding resource leo.gif
 - 8356320: fix tpix when we flood-fill a rect and tpix changes index
 - Merge branch 'master' of https://github.com/mickleness/jdk
 - Merge branch 'master' of https://github.com/mickleness/jdk
 - Merge branch 'master' of https://github.com/mickleness/jdk
 - Merge branch 'openjdk:master' into master
 - Merge branch 'openjdk:master' into master
 - Merge branch 'openjdk:master' into master
 - Merge pull request #5 from openjdk/master
 - ... and 4 more: https://git.openjdk.org/jdk/compare/898d4798...da529dcd

Changes: https://git.openjdk.org/jdk/pull/25076/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=25076&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8356320
  Stats: 141 lines in 3 files changed: 140 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/25076.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/25076/head:pull/25076

PR: https://git.openjdk.org/jdk/pull/25076