git: openjdk/jdk: 8295685: Update Libpng to 1.6.38

[Phil Race]

Changeset: b685fc2d
Author:    Harshitha Onkar <honkar at openjdk.org>
Committer: Phil Race <prr at openjdk.org>
Date:      2022-11-03 18:28:54 +0000
URL:       https://git.openjdk.org/jdk/commit/b685fc2de4d2847de2d1efaab2890646257ea6d3

8295685: Update Libpng to 1.6.38

Reviewed-by: prr, azvegint

! src/java.desktop/share/legal/libpng.md
! src/java.desktop/share/native/libsplashscreen/libpng/CHANGES
! src/java.desktop/share/native/libsplashscreen/libpng/LICENSE
! src/java.desktop/share/native/libsplashscreen/libpng/README
! src/java.desktop/share/native/libsplashscreen/libpng/UPDATING.txt
! src/java.desktop/share/native/libsplashscreen/libpng/png.c
! src/java.desktop/share/native/libsplashscreen/libpng/png.h
! src/java.desktop/share/native/libsplashscreen/libpng/pngconf.h
! src/java.desktop/share/native/libsplashscreen/libpng/pngget.c
! src/java.desktop/share/native/libsplashscreen/libpng/pnglibconf.h
! src/java.desktop/share/native/libsplashscreen/libpng/pngpriv.h
! src/java.desktop/share/native/libsplashscreen/libpng/pngread.c
! src/java.desktop/share/native/libsplashscreen/libpng/pngrtran.c
! src/java.desktop/share/native/libsplashscreen/libpng/pngrutil.c
! src/java.desktop/share/native/libsplashscreen/libpng/pngset.c
! src/java.desktop/share/native/libsplashscreen/libpng/pngstruct.h