Replace async awaitRedraw by sync window.paint(window.graphics), refactor Direct 3D and Metal redrawers (#146)

* Refactor Direct3DContextHandle - move `device` to Direct3DRedrawer.kt

* Refactor finishFrame: split into Direct3DContextHandler.flush and Direct3DRedrawer.swap

* DirectX: redraw immediately

* Metal: redraw immediately

* Remove awaitRedraw

* Fix screenshot tests on macOs

* Discussions