RFR: JDK-8321984: IGV: Upgrade to Netbeans Platform 20 [v4]

[Tobias Holenstein]

> Upgraded IGV and dependencies to the newest Netbeans Platform 20 which was released on December 2023.
> 
> Tested that IGV still behaves as expected after the upgrade.

Tobias Holenstein has refreshed the contents of this pull request, and previous commits have been removed. The incremental views will show differences compared to the previous content of the PR. The pull request contains two new commits since the last revision:

 - make IGV build work with mainline JDK version
 - remove requirement for nashorn

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Changes:
  - all: https://git.openjdk.org/jdk/pull/17106/files
  - new: https://git.openjdk.org/jdk/pull/17106/files/f986934d..35080de7

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=17106&range=03
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=17106&range=02-03

  Stats: 20 lines in 2 files changed: 5 ins; 5 del; 10 mod
  Patch: https://git.openjdk.org/jdk/pull/17106.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/17106/head:pull/17106

PR: https://git.openjdk.org/jdk/pull/17106