ns-openapi-3-1: allow normalization refractor plugins to work on scoped ApiDOM trees

[char0n]

Prelude

We have an issue with normalization during partial dereference in swagger-client. How it works currently is that the undereferenced definition gets normalized and then partially dereferenced. $$normalized flag is set on the dereferenced structure. This means that whatever got dereferencedd during dereferencing phase, will not be normalized. This creates various side effects and inconsistencies in derefencing. End use of SwaggerUI or SwaggerClient must not expected that anything that is referenced will get normalized.

More info in swagger-api/swagger-js#1396 (comment)

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Optimization

Implementation aligned above will require additional traversal pass. The moment all the plugins are idempotent, we can try incorporating them into dereference traversal.

[char0n]

All normalize refractor plugins have been made idempotent.