Bugfix #33004

Screencast recording stopped on a undo/redo. This was because all thread jobs
were killed then. Now it leaves screen jobs (screen cast) running, that's 
data that doesn't change on undos.

Also renamed jobs_stop_all() to jobs_kill_all() - it terminates threads.

source/blender/editors/render/render_opengl.c

@@ -333,8 +333,8 @@ static int screen_opengl_render_init(bContext *C, wmOperator *op)
 		return 0;
 	}
 
-	/* stop all running jobs, currently previews frustrate Render */
-	WM_jobs_stop_all(CTX_wm_manager(C));
+	/* stop all running jobs, except screen one. currently previews frustrate Render */
+	WM_jobs_kill_all_except(CTX_wm_manager(C), CTX_wm_screen(C));
 
 	/* create offscreen buffer */
 	sizex = (scene->r.size * scene->r.xsch) / 100;