hg: jdk8u/jdk8u-dev/jdk: 8217676: Upgrade libpng to 1.6.37

[zgu at redhat.com]

Changeset: 129d5c5426db
Author:    serb
Date:      2019-06-12 13:50 -0700
URL:       https://hg.openjdk.java.net/jdk8u/jdk8u-dev/jdk/rev/129d5c5426db

8217676: Upgrade libpng to 1.6.37
Reviewed-by: prr, jdv, kcr

! THIRD_PARTY_README
! make/lib/Awt2dLibraries.gmk
! src/share/native/sun/awt/libpng/CHANGES
! src/share/native/sun/awt/libpng/LICENSE
! src/share/native/sun/awt/libpng/README
! src/share/native/sun/awt/libpng/png.c
! src/share/native/sun/awt/libpng/png.h
! src/share/native/sun/awt/libpng/pngconf.h
! src/share/native/sun/awt/libpng/pngdebug.h
! src/share/native/sun/awt/libpng/pngerror.c
! src/share/native/sun/awt/libpng/pngget.c
! src/share/native/sun/awt/libpng/pnginfo.h
! src/share/native/sun/awt/libpng/pnglibconf.h
! src/share/native/sun/awt/libpng/pngmem.c
! src/share/native/sun/awt/libpng/pngpread.c
! src/share/native/sun/awt/libpng/pngpriv.h
! src/share/native/sun/awt/libpng/pngread.c
! src/share/native/sun/awt/libpng/pngrio.c
! src/share/native/sun/awt/libpng/pngrtran.c
! src/share/native/sun/awt/libpng/pngrutil.c
! src/share/native/sun/awt/libpng/pngset.c
! src/share/native/sun/awt/libpng/pngstruct.h
! src/share/native/sun/awt/libpng/pngtrans.c