chore: remove unnecessary assertion (#4867)

packages/reactivity/__tests__/ref.spec.ts

@@ -35,7 +35,6 @@ describe('reactivity/ref', () => {
     // same value should not trigger
     a.value = 2
     expect(calls).toBe(2)
-    expect(dummy).toBe(2)
   })
 
   it('should make nested properties reactive', () => {