Update libpng to latest 1.6.59 version, we use libpng in splashscreen implementation.
Testing is green with this libpng update. --------- - [x] I confirm that I make this contribution in accordance with the [OpenJDK Interim AI Policy](https://openjdk.org/legal/ai). ------------- Commit messages: - Update license - Update Changes: https://git.openjdk.org/jdk/pull/33237/files Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=33237&range=00 Issue: https://bugs.openjdk.org/browse/JDK-8393195 Stats: 66 lines in 11 files changed: 36 ins; 10 del; 20 mod Patch: https://git.openjdk.org/jdk/pull/33237.diff Fetch: git fetch https://git.openjdk.org/jdk.git pull/33237/head:pull/33237 PR: https://git.openjdk.org/jdk/pull/33237
