Ensure the registry remains consistent when toggling the database feature flag

While running the registry in mirrored mode, which will happen during the initial testing stages, we have to ensure that the filesystem metadata remains consistent if we toggle the database feature flag on and off. We have observed this during our local testing but further tests should be performed to double-check that this is the behavior.

Confirm get after database enabled write

• GET /v2/<name>/manifests/<reference> schema 1 (Covered indirectly by other tests)
• GET /v2/<name>/manifests/<reference> schema 2 !347 (merged)
• GET /v2/<name>/manifests/<reference> manifest list !348 (merged)
• GET /v2/<name>/blobs/<digest> !350 (merged)
• GET /v2/_catalog !351 (merged)
• GET /v2/<name>/tags/list !352 (merged)