Random behat failures with tool_customlang scenarios (timeout)

Regression testing

1. Go to Admin > general > Language customisation
2. Choose "English"
3. Press the "Open language pack for editing" button.
4. Verify that a progress bar appear with text "Language pack loaded"text once finished.
5. Press the "continue" button.
6. Verify that now you are in the "Filter strings" page.
7. Verify that in the menu list of components, there is a "mod" bold element and, under it, there are multiple files, one for every mod plugin (assign.php, assignment.php, bitgluebutton.php...). And many more, more bold elements (auth, blocks...) all of them having various .php under them.
8. Select in the menu list the "mod -> forum.php" element and click the "Show strings" button.
9. Verify that after the filter, a long list of strings is shown, with an edit box on the right.
10. Find the "addreply" string and, in the edit box type "Answer to the POST"
11. Go to the end of the page and press the "Apply changes and continue editing" button.
12. Verify that the "addreply" element now has a blue background and that the "Answer to the POST" text is there, in the edit box.
13. Go to the end of the page and press the "Save changes to the language pack" button.
14. Verify that in the confirmation page there is the "There are 1 modified strings" text.
15. Press "Continue" (that will save the customised lang pack).
16. Go to any forum in any course in the site (create one if needed).
17. Click the "Reply" link for any of the posts in the forum, then "Advanced"
18. Verify that in the navigation bar you can see the "Answer to the POST" text that was customised some steps above (see screenshot).
    
19. That's all, the language customisation is working ok and the changes in this issue don't affect it.

Automated testing

• The repetitions that have been executed as part of this issue, both with super-slow local oracle environment and @ CI (see ToBiC comment) should be enough. Zero failures where they used to happen lots of time.