Uneven frame pacing with vsync (#4744)

fixes issue #3906

src/Ryujinx.Graphics.Gpu/Engine/GPFifo/GPFifoDevice.cs

@@ -252,6 +252,7 @@ namespace Ryujinx.Graphics.Gpu.Engine.GPFifo
         public void Interrupt()
         {
             _interrupt = true;
+            _event.Set();
         }
 
         /// <summary>