RFR: JDK-8321984: IGV: Upgrade to Netbeans Platform 20

[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.

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Commit messages:
 - JDK-8321984: IGV: Upgrade to Netbeans Platform 20

Changes: https://git.openjdk.org/jdk/pull/17106/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=17106&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8321984
  Stats: 10 lines in 1 file changed: 0 ins; 0 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