[Fix #338][Fix #350] Fix a false positive for Rails/IndexBy and Rails/IndexWith

[eugeneius]

If the each_with_object hash is used in the transformed key or value, Rails/IndexBy or Rails/IndexWith can't be used.

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• Commit message starts with [Fix #issue-number] (if the related issue exists).
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• Squashed related commits together.
• Added tests.
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[koic]

Thanks!