RuboCop exception handling of autocorrecting cop has multiple issues

[marcandre]

While working on #7868, I realized that RuboCop's exception handling of autocorrecting cop has issues:

1. some exceptions may be completely ignored:

# my_cop.rb:
module Custom
  class MyCop < RuboCop::Cop::Cop
    MSG = "let's be positive"

    def on_send(node)
      if node.method_name == :-
        add_offense(node)
        raise 'oh!'  # <<< Completely ignored!
      end
    end

    def autocorrect(node)
      -> (corrector) do
        corrector.replace(node.loc.selector, '+')
      end
    end
  end
end

> echo "2-2" | rubocop -r ./my_cop.rb --only Custom -a -s "test"

Inspecting 1 file
C

Offenses:

test:1:1: C: [Corrected] Custom/MyCop: let's be positive
2-2
^^^

1 file inspected, 1 offense detected, 1 offense corrected
====================
2+2

2. as noted in Improving auto correction's API #7868, some exceptions will crash rubocop (move the raise inside the -> in the example above)

There are 3 specs for this handling in team_spec, but 1 is redundant with the previous spec, and there are quite a few cases missing and don't test the interaction with Runner. For example this spec fails if we add let(:options) { { auto_correct: true } }.

I don't intend on cleaning this up before #7868 is completed. It should be easier to deal with too as the current autocorrection timing is quite intricate.

[marcandre]

I believe this to be fixed in #7868