git: openjdk/jdk: 8316030: Update Libpng to 1.6.40

[Harshitha Onkar]

Changeset: 158293d2
Author:    Harshitha Onkar <honkar at openjdk.org>
Date:      2023-10-20 17:35:21 +0000
URL:       https://git.openjdk.org/jdk/commit/158293d2517695f8c5eaca1b46ecf0f1f9f09691

8316030: Update Libpng to 1.6.40

Reviewed-by: prr, dnguyen

! 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/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/pngset.c