Improve Absolute Zero Mode by 15-30%

Short-circuits out of the Render function in the main program loop.

With an NES game running at 8500 FPS before, this brings it to 9700 FPS.

With no game loaded, running at 45k FPS, this brings it to 60k FPS.

BizHawk.Client.EmuHawk/MainForm.cs

@@ -1906,6 +1906,10 @@ namespace BizHawk.Client.EmuHawk
 
 		private void Render()
 		{
+			if (Global.Config.DispSpeedupFeatures == 0)
+			{
+				return;
+			}
 			//private Size _lastVideoSize = new Size(-1, -1), _lastVirtualSize = new Size(-1, -1);
 			var video = Global.Emulator.VideoProvider();
 			//bool change = false;