Fix Splash example crash

We can close the window during onRender

skiko/src/jvmMain/kotlin/org/jetbrains/skiko/SkiaLayer.kt

@@ -102,14 +102,15 @@ open class SkiaLayer : HardwareLayer() {
 
         renderer?.onRender(canvas, pictureWidth, pictureHeight, nanoTime)
 
-        check(!isDisposed)
-
+        // we can dispose layer during onRender
+        if (!isDisposed) {
             synchronized(pictureLock) {
                 picture?.instance?.close()
                 val picture = pictureRecorder.finishRecordingAsPicture()
                 this.picture = PictureHolder(picture, pictureWidth, pictureHeight)
             }
         }
+    }
 
     override fun draw() {
         check(!isDisposed)