Tests: fix TestCase for phpunit 9

[yookoala]

Description

• Fix forward all unit test compatibiliy with phpunit 9 by updating setUp and tearDown function signatures.

Motivation and Context

• Newer PHPUnit TestCase setUp and tearDown method needs to specifically hint to return "void".
• The change is backward compatible. Loose parent methods are compatible with strict children implementations.
• This fixed a few errors that block PHPUnit / Codeception errors in PHP 8 #1214.

How Has This Been Tested?
On CI platform.

[SKuipers]

Thanks! You're really streamlining the test process. I know we were frozen on the same PHPUnit/Codeception versions for a while to try and keep things from breaking, great to see you updating these and untangling the issues. Hugely appreciated 😃