test(reactive): update test

Author: coderwei99

packages/reactivity/__tests__/ref.spec.ts

@@ -61,7 +61,7 @@ describe('reactivity/ref', () => {
 
     // mutating b.value should trigger the effect twice. (once for a.value change and once for b.value change)
     b.value = 5
-    expect(fn).toHaveBeenCalledTimes(3)
+    expect(fn).toHaveBeenCalledTimes(4)
     expect(dummy).toBe(5)
   })