Kill phpunit tests external dependencies...

We need to look for external dependencies in unit tests and, when possible and not needing to use external systems, provide in-house testing for them (say local resources, exttest support...).

This was created as a followup of MDL-49631, where one of those external dependencies (not really needed) was detected.

Would be great to analyze all them together, maybe marking the "valid" ones in some way.

Ciao