Prevent needRedraw reentry on iOS (#769)

* Move flush to `finally` block.

* Prevent reentry when scene is invalidated within draw.

* Revert "Move flush to `finally` block."

This reverts commit 25b04b811c2425c27a04b7508dbd7de70b8ef735.

* Prevent within frameListener as well.

skiko/src/iosMain/kotlin/org/jetbrains/skiko/redrawer/MetalRedrawer.ios.kt

@@ -80,9 +80,9 @@ internal class MetalRedrawer(
             }
 
             DrawSchedulingState.SCHEDULED_ON_NEXT_FRAME -> {
-                drawIfLayerIsShowing()
-
                 drawSchedulingState = DrawSchedulingState.AVAILABLE_ON_NEXT_FRAME
+
+                drawIfLayerIsShowing()
             }
 
             DrawSchedulingState.AVAILABLE_ON_CURRENT_FRAME -> {
@@ -164,9 +164,9 @@ internal class MetalRedrawer(
             }
 
             DrawSchedulingState.AVAILABLE_ON_CURRENT_FRAME -> {
-                drawIfLayerIsShowing()
-
                 drawSchedulingState = DrawSchedulingState.AVAILABLE_ON_NEXT_FRAME
+
+                drawIfLayerIsShowing()
             }
 
             DrawSchedulingState.SCHEDULED_ON_NEXT_FRAME -> {