RFR: JDK-8233381 Update copyright year in build system files

[Magnus Ihse Bursie]

I noticed that the copyright year was not properly updated to 2019 in 
multiple make files that was indeed modified in 2019.

Bug: https://bugs.openjdk.java.net/browse/JDK-8233381
WebRev: 
http://cr.openjdk.java.net/~ihse/JDK-8233381-update-copyright-year-2019/webrev.01

/Magnus