[13] RFR: JDK-8209086: Some javafx.web files are missing GPLv2+Classpath copyright header

[Kevin Rushforth]

Please review this fix to add a GPLv2+Classpath copyright header to 
those javafx.web native files that are missing the header.

https://bugs.openjdk.java.net/browse/JDK-8209086
https://github.com/javafxports/openjdk-jfx/pull/533

-- Kevin