Invoking @BeforeClass and @AfterClass methods on robolectric class loader classes.

@Test methods are called on class instances from the robolectric class loader,
however the @BeforeClass and @AfterClass methods were not, making any code
within these methods useless to @Test methods since both belonged to different
namespaces.

This patch makes the @BeforeClass and @AfterClass invocations on classes in
the right class loader.