chore: remove duplicate test (#8003)

packages/runtime-core/__tests__/vnode.spec.ts

@@ -220,7 +220,6 @@ describe('vnode', () => {
     const node2 = createVNode({}, null, [node1])
     const cloned2 = cloneVNode(node2)
     expect(cloned2).toEqual(node2)
-    expect(cloneVNode(node2)).toEqual(node2)
     expect(cloneVNode(node2)).toEqual(cloned2)
   })