Test canonical compare for NSEC in incremental signing.

[Philip-NLnetLabs]

Provide your description here

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• If you are changing Rust code or integration tests (Cargo.*, crates/, etc/, integration-tests/, src/):
  • Did you run the integration tests with act through the act-wrapper (as described in TESTING.md)?

[bal-e]

Looks alright -- but it's hard (time-consuming) to figure out exactly what is changing in the zonefiles. I'd love to find a way, in the future, of generating these zonefiles programmatically, so the differences become more clear.

[Philip-NLnetLabs]

I maintain them using:
$ diff -u zones/incremental-signing-test1-input*

[Philip-NLnetLabs]

Would it help if I add the diff command to the top of each zone file?

[bal-e]

I'll use diff and review again.