Can't cancel view edit if error present

Problem/Motivation

When editing a view, if you get to a point where there is an error and decide to simply Cancel and start editing again, clicking Cancel won't cancel the editing until the error is resolved. This because a problem when I couldn't actually edit the setting that was generating the error (still working on characterizing it but it appears to be related to #2634198: Not possible to edit another view display → ), so I couldn't back out and I couldn't solve the issue.

Proposed resolution

Clicking Cancel shouldn't care if there is an error, it should discard the edits to that point and return to the Views list page.

To reproduce the error:

1. I went to simplytest.me and create a new 8.0.3 site.
2. I went to Structure>>Views and Added a new view, Can't Cancel, with a block that was an unformatted list of titles.
3. When I got to the edit screen, I clicked Save to ensure everything to that point was saved.
4. I added a page display, which starts out with no path set
5. Clicking cancel without setting a path returns to the edit screen for the view with the "Display "Page" uses a path but the path is undefined." error and unsaved changes messages.

Export of the view (without the Page display) is attached.