[12] RFR: JDK-8211304: [macOS] Crash on focus loss from dialog on macOS 10.14 Mojave

[Kevin Rushforth]

Pankaj & Arun,

Please review (on Github) the fix for the macOS 10.14 Mojave crash:

https://bugs.openjdk.java.net/browse/JDK-8211304
https://github.com/javafxports/openjdk-jfx/pull/271

-- Kevin