[Bug Report] destroy-on-close in el-dialog will invoke inner component's created method

### Element UI version
2.13.0

### OS/Browsers version
chrome

### Vue version
2.6.11

### Reproduction Link
https://codepen.io/duan1993/pen/eYNMdxZ

### Steps to reproduce
1. click "点击打开 Dialog" button, will alert(1)
2. click "X" button, will alert(1) again

### What is Expected?
when click "X" button, will not alert(1)

### What is actually happening?
when click "X" button, will alert(1)