fix(state/file): populate `change` on touch

Previously when a file was touched, the `changes` field was never
populated. This commit fixes this.

I decided to have this as a separate pull request from #11269 since someone might object to populating `changes` field for touch changes. Maybe that would disturb someone who has a state that constantly updates that mtime/atime. My counter argument is that a change is a change, and it should be documented.