## Changes
The CLI test runner instantiates a new CLI "instance" through
`cmd.New()` and runs it with specified arguments. This is as close as we
get to running the real CLI **in-process**. This runner was located in
the `internal` package next to other helpers. This change moves it to
its own dedicated package.
Note: this runner transitively imports pretty much the entire
repository, which is why we intentionally keep it _separate_ from
`testutil`.
## Tests
n/a
Pieter Noordhuis