Use wxDELETE() and wxDELETEA() when possible.

Use wxDELETE[A]() functions which automatically NULL out their arguments after
deleting them instead of doing it manually.

Closes #9685.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@64656 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/msw/cursor.cpp

@@ -105,8 +105,7 @@ public:
 
     virtual void OnExit()
     {
-        delete gs_globalCursor;
-        gs_globalCursor = NULL;
+        wxDELETE(gs_globalCursor);
     }
 };