Unit test fixes

[bwalkerl]

Partial unit test fixes for t19 that are simple and universal.

• PHPUnit 10+: Requires data providers to be static. - but this is a safe change for all versions
• Totara expects unit test classes formatted a specific way. This doesn't fully address that as it may require flattening the structure and would be better suited for a branch with all T19 fixes. Instead, this just resolves the phpunit warning for "Class cleaner_test cannot be found" - which relies on the filename being in the class name.

Fixes for other breaking changes are likely better on a new branch.

[djarran]

Looks good, merging