Refactor cli.test.js (#5266)
Refactor cli.test.js (#5266)

This refactoring aims to make the code more readable by reducing duplication.

E.g.

```diff
-replaceBackslashes(path.join(fixturesPath, 'config-block-no-empty.json')),
+fixturesPath('config-block-no-empty.json'),
```
stylelint/stylelint,stylelint/stylelint,stylelint/stylelint,stylelint/stylelint