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/motif/dialog.cpp

@@ -307,8 +307,7 @@ int wxDialog::ShowModal()
     // Now process all events in case they get sent to a destroyed dialog
     wxFlushEvents( display );
 
-    delete m_eventLoop;
-    m_eventLoop = NULL;
+    wxDELETE(m_eventLoop);
 
     // TODO: is it safe to call this, if the dialog may have been deleted
     // by now? Probably only if we're using delayed deletion of dialogs.