Use a ParametersRunnerFactory for creating the test for a set of parameters.

There's now an explicit component for creating the runner of a single set of parameters. IMHO this is a better extension point than overriding a method.

The factory can be specified by the @UseParametersRunnerFactory
annotation or you can subclass the Parameterized class and provide
the factory to its constructor.
Use List instead of array.

Handling lists is easier than handling arrays.