RFR: JDK-8348598 : Update Libpng to 1.6.47 [v3]

[Harshitha Onkar]

> Upgraded Libpng to v1.6.47

Harshitha Onkar has updated the pull request incrementally with one additional commit since the last revision:

  header update

-------------

Changes:
  - all: https://git.openjdk.org/jdk/pull/24021/files
  - new: https://git.openjdk.org/jdk/pull/24021/files/e1954bcb..2f0cea2d

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=24021&range=02
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=24021&range=01-02

  Stats: 82 lines in 16 files changed: 80 ins; 2 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/24021.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/24021/head:pull/24021

PR: https://git.openjdk.org/jdk/pull/24021