Don't assume `basic-page` exists as a template when running WireTests

[jlahijani]

In Fieldgroups.test.php there is this test:

$this->check('$fieldgroups->get(basic-page) returns Fieldgroup', true, $fieldgroups->get('basic-page') instanceof Fieldgroup);

It assumes the site has a template called basic-page. I always rename it to just basic because then when I make the associated page class file, it will be class BasicPage instead of class BasicPagePage (which sounds silly).

So the way the test is written will fail given that I rename basic-page template to simply basic.