Fix corner resize for multi-point arrows (#1105)

The logic to support it was not implemented. This is not the prettiest way to solve it in the world but it does work. Some more refactoring here is probably warranted.

Fixes #1039

src/element/handlerRectangles.ts

@@ -131,13 +131,6 @@ export function handlerRectangles(
         } as typeof handlers;
       }
     }
-
-    return {
-      n: handlers.n,
-      s: handlers.s,
-      w: handlers.w,
-      e: handlers.e,
-    } as typeof handlers;
   }
 
   return handlers;