8.0-controls-scrum-h44: up to 35% regression in Controls.TableView and Controls.Buttons benchmarks

There are following regression reported by Aurora in build 8.0-controls-scrum-h44:

Win7-High-End
=============
Controls.TableView-Keyboard: -5% (-10.61 fps)
Controls.TableView-XmasTree: -13% (-7.26 fps)

Mac-Low-Range
=============
Controls.TableView-Keyboard: -18% (-13.33 fps)
Controls.TableView-Mouse: -16% (-10.32 fps)
Controls.TableView-MoveRows: -18% (-11.21 fps)
Controls.TableView-XmasTree: -36% (-8.88 fps)


The regressions are caused by integrated RT-22429 "Region optimizations" as this is
the only fix went into 8.0-controls-scrum-h44.

I ran Controls.TableView-XmasTree with slightly different configuration (benchmark arguments) and
got -20% regression from 225 fps to 180 fps on Win7-High-End machine.

JPA profile shows that the time spent in com.sun.javafx.sg.prism.NGRegion.renderContent
has been increased from 27.972 sec to 31.522 sec.

Steps to run Controls.TableView-XmasTree:
> cd JFX_WS/tests/performance/Controls/
> ant
> java -Xmx512m -Djavafx.animation.fullspeed=true
       -cp "JFX_HOME/rt/lib/jfxrt.jar;./dist/Controls.jar;../FXBenchmark/dist/FXBenchmark.jar;../../../import/benchmarks-2.1.1/benchmarks-2.1.1.jar"
       jrockit.bm.Main controls.bm.XmasTreeTableViewBenchmark -i 1 -wt 0 -tr 60 -col-width 40 -row-height 20 -rows 30 -columns 30 -batch-size 10