Add tests for expect_no_corrections and expect_correction loop behaviour

[Earlopain]

This relates to #12763 and #12774, where behaviour for these two methods was changed. Undoing changes from these PRs will make these new tests fail.

I thought it would be nice to explicitly test against since there shouldn't ever be code here where this behaviour is actually triggered. I haven't found a place where the expectations were already tested so I made a new file for that.

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[bbatsov]

I'm OK with the proposed changes. @koic are you okay with the suggested location for the tests?

[koic]

Considering spec/rubocop/rspec_expect_offense_spec.rb, it seems better to place it as spec/rubocop/rspec/expect_offense_spec.rb to form the testing pair with lib/rubocop/rspec/expect_offense.rb.