This test wasn't running by default, so we missed that it wasn't
actually being executed - or that it was failing when running in the
testing environment.
As far as I can tell this is not, and has not, been used either in core
or in any tap, third party or otherwise, so just remove the feature and
its test.
Dependency is another similar, related class and it's super confusing
to have some Requirements that are named *Dependency.
ClosesHomebrew/homebrew#38891.
Signed-off-by: Mike McQuaid <mike@mikemcquaid.com>
