RFR: 8345039: IGV: save user-defined node colors to XML [v3]

[Tobias Holenstein]

> This PR depends on https://github.com/openjdk/jdk/pull/22402 
> 
> [JDK-8343535](https://bugs.openjdk.org/browse/JDK-8343535) introduced the possibility to give user-defined colors to a node.
> The colors are lost when the user goes to the next graph or when IGV is closed. Save the colors as a property of the graph to the XML to make it more permanent. This requires that the user can also remove the colors again.
> 
> <img width="474" alt="color" src="https://github.com/user-attachments/assets/c994f93c-7db1-40e6-9963-2f5417cec77f">
> 
> ### Whats new
> - Now colors are saved with the XML as well
> - Colors are kept when changing to a different graph
> - The user can remove the color again: This uses the color from the filter or WHITE otherwise

Tobias Holenstein 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 18 additional commits since the last revision:

 - Merge branch 'master' into JDK-8345039
 - patch2: fix botton on linux
 - patch1
 - JDK-8345039: IGV: save user-defined node colors to XML
 - revert copyright changes
 - fixed graph objects equality
 - remove executability of igv.sh
 - update Figure height calculation for Slots
 - run IGV without asserts
 - batch add connectionLayer.addChildren(newWidgets);
 - ... and 8 more: https://git.openjdk.org/jdk/compare/df08c533...001a073a

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/22440/files
  - new: https://git.openjdk.org/jdk/pull/22440/files/e58c6171..001a073a

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=22440&range=02
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=22440&range=01-02

  Stats: 62313 lines in 1516 files changed: 28722 ins; 26121 del; 7470 mod
  Patch: https://git.openjdk.org/jdk/pull/22440.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/22440/head:pull/22440

PR: https://git.openjdk.org/jdk/pull/22440