WebNode.GUIMark2-Bitmap benchmark hangs starting from build 8.0-graphics-scrum-349.
Stack trace of hanged process shows some deadlock where "JavaFX Application thread" is waiting
at com.sun.webkit.graphics.WCRenderQueue.flush(WCRenderQueue.java:94)
for the future task, but the same task is blocked by an object monitor on QuantumRenderer-0 thread.


Steps to run the benchmark:
> cd JFX_WS/tests/performance/WebNodeTestSuite
> ant
> java client -Djava.library.path=../FXBenchmark/lib/win32/
       -cp "JFX_HOME/rt/lib/jfxrt.jar;./dist/WebNodeTestSuite.jar;../FXBenchmark/dist/FXBenchmark.jar;../../../import/benchmarks-2.1.1/benchmarks-2.1.1.jar"
       webnodetestsuite.GUIMark2 -resource guimark2-bitmap.html


The issue is observed on both Windows and MacOS systems.
The issue is still present in latest available build 8.0-graphics-scrum-360.