fix(runtime-dom): fix v-on same computed handler on multiple elements

fix #1747

packages/runtime-dom/__tests__/patchEvents.spec.ts

@@ -119,4 +119,38 @@ describe(`runtime-dom: events patching`, () => {
     expect(fn1).toHaveBeenCalledTimes(1)
     expect(fn2).toHaveBeenCalledTimes(0)
   })
+
+  // #1747
+  it('should handle same computed handler function being bound on multiple targets', async () => {
+    const el1 = document.createElement('div')
+    const el2 = document.createElement('div')
+
+    const event = new Event('click')
+    const prevFn = jest.fn()
+    const nextFn = jest.fn()
+
+    patchProp(el1, 'onClick', null, prevFn)
+    patchProp(el2, 'onClick', null, prevFn)
+
+    el1.dispatchEvent(event)
+    el2.dispatchEvent(event)
+    await timeout()
+    expect(prevFn).toHaveBeenCalledTimes(2)
+    expect(nextFn).toHaveBeenCalledTimes(0)
+
+    patchProp(el1, 'onClick', prevFn, nextFn)
+    patchProp(el2, 'onClick', prevFn, nextFn)
+
+    el1.dispatchEvent(event)
+    el2.dispatchEvent(event)
+    await timeout()
+    expect(prevFn).toHaveBeenCalledTimes(2)
+    expect(nextFn).toHaveBeenCalledTimes(2)
+
+    el1.dispatchEvent(event)
+    el2.dispatchEvent(event)
+    await timeout()
+    expect(prevFn).toHaveBeenCalledTimes(2)
+    expect(nextFn).toHaveBeenCalledTimes(4)
+  })
 })