Mutation of super to super() should not happen for a method with no arguments

[dgollahon]

From @mvz on July 16, 2016 11:48

(Follow-up from #309).

It looks like mutant wants to enforce super() as opposed to super, even when those two options are completely equivalent:

class Foo
  def bar
    # ...
  end
end

class Bar < Foo
  def bar
    # ...
    super
  end
end

Here, idiomatic Ruby would favor super over super(), but mutant wants me to use super(), and I see no way to write a spec to favor super.

Copied from original issue: mbj/mutant#615