GTK display refresh rate is throttled

Guest OS running with GL enabled GTK display shows a reduced refresh rate, e.g. moving cursor around with iGVT-g DMA Buf.

It seems that a default refresh interval GUI_REFRESH_INTERVAL_DEFAULT (30ms) is defined in include/ui/console.h, throttling the display refresh rate at 33Hz.

To correct this throttle issue, a shorter interval should be applied to display change listener or the default value should be used.