Fixes [JDK-8201567](https://bugs.openjdk.java.net/browse/JDK-8201567).
------------- Commit messages: - 8201567: QuantumRenderer modifies buffer in use by JavaFX Application Thread Changes: https://git.openjdk.java.net/jfx/pull/255/files Webrev: https://webrevs.openjdk.java.net/jfx/255/webrev.00 Issue: https://bugs.openjdk.java.net/browse/JDK-8201567 Stats: 35 lines in 5 files changed: 29 ins; 0 del; 6 mod Patch: https://git.openjdk.java.net/jfx/pull/255.diff Fetch: git fetch https://git.openjdk.java.net/jfx pull/255/head:pull/255 PR: https://git.openjdk.java.net/jfx/pull/255
