Upgrade libpng used for Splashscreen from 1.6.51 to 1.6.54 version. Testing is green with this update.
------------- Commit messages: - 8375063: Update Libpng to 1.6.54 Changes: https://git.openjdk.org/jdk/pull/29292/files Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=29292&range=00 Issue: https://bugs.openjdk.org/browse/JDK-8375063 Stats: 1406 lines in 16 files changed: 443 ins; 7 del; 956 mod Patch: https://git.openjdk.org/jdk/pull/29292.diff Fetch: git fetch https://git.openjdk.org/jdk.git pull/29292/head:pull/29292 PR: https://git.openjdk.org/jdk/pull/29292
