The signatures of these methods will change in PHPUnit 9, and in
general, having these methods means additional code to maintain. Since
this is test code, any attempt to use these traits from a class which
doesn't have the required methods will fail hard, and as such, there's
no reason to have these methods at all.
Also, MockServiceDependenciesTrait was redeclaring fail() as a
non-static method, but it is actually static in the parent class, which
makes tests fail on PHP 8.
Bug: T243600
Change-Id: I78bf1bdd2eb2e09aed27d1b6bff2302e28600703
4877132223