removed deps checks in unit tests
removed deps checks in unit tests

As Composer is now widely used in the PHP world, having to run composer
install before running the test suite is expected. This also has the
nice benefit of removing a bunch of code, making things easier to
maintain (there is only one place to declare a dev dependency), and
probably more.

oswaldderiemaecker/ClassLoader,symfony/ClassLoader,symfony/class-loader,cyrrill/loader