Update libpng to latest 1.6.57 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: - 8382047: Update Libpng to 1.6.57 Changes: https://git.openjdk.org/jdk/pull/30716/files Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=30716&range=00 Issue: https://bugs.openjdk.org/browse/JDK-8382047 Stats: 89 lines in 9 files changed: 58 ins; 0 del; 31 mod Patch: https://git.openjdk.org/jdk/pull/30716.diff Fetch: git fetch https://git.openjdk.org/jdk.git pull/30716/head:pull/30716 PR: https://git.openjdk.org/jdk/pull/30716
