RFR: 8351913: ToolkitImage renders some gifs wrong [v3]

[Jeremy Wood]

> I do not have much background in LZW compression or in C, but I'm reasonably confident this resolves the problem I'm observing. It looks like the GifImageDecoder was not always correctly handling compression codes after the table reached its limit of ~4096. If anyone has suggestions for improvements I'm happy to make adjustments.
> 
> Luckily while debugging this: I was able to compare the flawed implementation (GifImageDecoder) with ImageIO's implementation (GIFImageReader) to help identify how the suffix/prefix tables are supposed to work.
> 
> ImageIO's implementation may have suffered a similar bug (maybe https://bugs.openjdk.org/browse/JDK-7131823 ?), and that appears to have been backported.
> 
> I have dozens of additional test cases for this problem, but unfortunately I don't have the rights to commit them to the OpenJDK repo. Feel free to email me for additional context/test cases.

Jeremy Wood has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains 17 additional commits since the last revision:

 - Merge branch 'master' into JDK-8351913
 - Merge branch 'master' of https://github.com/mickleness/jdk
 - Merge branch 'master' of https://github.com/mickleness/jdk
 - 8351913: changing whitespace (PR review)
 - 8351913: changing whitespace
   
   These are flagged as "Whitespace errors" by an automated OpenJDK script
   
   https://github.com/openjdk/jdk/pull/24271/checks?check_run_id=39489913895
 - Merge branch 'master' into JDK-8351913
 - Merge branch 'master' of https://github.com/mickleness/jdk
 - 8351913: code cleanup
 - 8351913: support decoding LZW image data with 4095 entries
 - Merge branch 'openjdk:master' into master
 - ... and 7 more: https://git.openjdk.org/jdk/compare/ad29194c...d555631c

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/24271/files
  - new: https://git.openjdk.org/jdk/pull/24271/files/e2ab9492..d555631c

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=24271&range=02
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=24271&range=01-02

  Stats: 271008 lines in 2137 files changed: 70273 ins; 193504 del; 7231 mod
  Patch: https://git.openjdk.org/jdk/pull/24271.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/24271/head:pull/24271

PR: https://git.openjdk.org/jdk/pull/24271