fill_in with empty string does not call addEventListener('input')

Hello!

I'm testing cuprite to replace chromedriver in our test suite and I've noticed a weird behaviour using `fill_in :element, with: ''`.
When doing this in an input text it does not fire the event `input`.

I have the following JS code:
```
input.addEventListener('input', (e) => {
  console.log("Hello")
})
```
Never called when the input is filled with empty string.