Lets minimize the code path that is allowed to raise "shallowed" mutations.

Currently we evaluate `command_line_arguments` that triggers lots of code within `::Mutant`.

```
def run
  null = StringIO.new
  args = command_line_arguments
  begin
    !::RSpec::Core::Runner.run(args, null, null).zero?
  rescue StandardError
    true
  end
end
```

This way we dont shadow lots of mutant erorrs!