Allow calling wxListCtrl::SetImageList() before Create() in wxMSW

This already worked with the generic version, but silently failed with
wxMSW, so make it work with wxMSW too as it doesn't cost much and makes
wxListCtrl behave in the same way under all platforms.

Also document that SetImageList() can be used before the window is
created.

interface/wx/listctrl.h

@@ -1110,6 +1110,11 @@ public:
         This method does not take ownership of the image list, you have to
         delete it yourself.
 
+        Note that, unlike for most of the other methods of this class, it is
+        possible to call this function before the corresponding window is
+        created, i.e. do it in a constructor of a class derived from wxListCtrl
+        before calling Create().
+
         @see AssignImageList()
     */
     void SetImageList(wxImageList* imageList, int which);