RFR: JDK-8348598 : Update Libpng to 1.6.47 [v2]

[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/b8f10b8d..e1954bcb

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=24021&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=24021&range=00-01

  Stats: 5 lines in 1 file changed: 5 ins; 0 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