`onBlur` is producing an "alien" message when user go back to history in Chrome

[owanturist]

Let's imagine an input with onBlur handling. When user focus the input and go back to history elm produce a wrong message which go to current module.
In most cases it's going to be an source of JS error and elm app will be fallen in a result.

In Ellie example you can see both of cases: soft error when app doesn't fall (see at logs) and fatal error.

OS: macOS High Sierra 10.13.3
Browser: Google Chrome 63.0.3239.132 (Official Build) (64-bit)
Elm version: 0.18.0

I hope it will help to make Elm little bit more stable and better.

[process-bot]

Thanks for the issue! Make sure it satisfies this checklist. My human colleagues will appreciate it!

Here is what to expect next, and if anyone wants to comment, keep these things in mind.

[rowland]

Related: elm/compiler#2069 (comment)