revert: test(runtime-vapor): add misc test

This reverts commit 63dbc26f3464db7b2db103f891ad42a738b6c5b5.
https://github.com/vuejs/core-vapor/pull/246

packages/runtime-vapor/__tests__/misc.spec.ts

@@ -1,14 +0,0 @@
-import { isReactive, reactive } from 'vue'
-import { makeRender } from './_utils'
-
-const define = makeRender()
-
-describe('misc', () => {
-  test.fails('component public instance should not be observable', () => {
-    const { instance } = define({}).render()
-    expect(instance).toBeDefined()
-    const r = reactive(instance!)
-    expect(r).toBe(instance)
-    expect(isReactive(r)).toBe(false)
-  })
-})