RFR: JDK-8229328: [windows] PlatformFileHandle type should be JGObject rather than void *

[Guru]

Hi, 

Please review the fix for 
JBS : https://bugs.openjdk.java.net/browse/JDK-8229328 <https://bugs.openjdk.java.net/browse/JDK-8229328>
PR : https://github.com/javafxports/openjdk-jfx/pull/555 <https://github.com/javafxports/openjdk-jfx/pull/555> 

Root cause and Solution updated in JBS.

Thanks,
Guru