Fix tests to avoid inferred width ports on public modules.

[dtzSiFive]

Public modules can't have inferred widths or abstract reset, fix tests to emit spec-compliant FIRRTL 4.0.

Contributor Checklist

• Did you add Scaladoc to every public function/method?
• Did you add at least one test demonstrating the PR?
• Did you delete any extraneous printlns/debugging code?
• Did you specify the type of improvement?
• Did you add appropriate documentation in docs/src?
• Did you request a desired merge strategy?
• Did you add text to be included in the Release Notes for this change?

Type of Improvement

• API modification

Desired Merge Strategy

• Squash: The PR will be squashed and merged (choose this if you have no preference).

Release Notes

Main module are "public" (#3813, soon mandatory) which means they cannot have inferred widths or abstract resets. Code relying on old behavior will presently encounter an error in firtool.

Reviewer Checklist (only modified by reviewer)

• Did you add the appropriate labels? (Select the most appropriate one based on the "Type of Improvement")
• Did you mark the proper milestone (Bug fix: 3.6.x, 5.x, or 6.x depending on impact, API modification or big change: 7.0)?
• Did you review?
• Did you check whether all relevant Contributor checkboxes have been checked?
• Did you do one of the following when ready to merge:
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[dtzSiFive]

CI failure re:jextract is due to the usual problem of the URL expiring, and is fixed here: #3868 .

[seldridge]

LGTM

One questions about if this needs output coercion or not.

[dtzSiFive]

This is marked "API modification" label -- that's so release notes flag it as such, right? Sounds good to me.
I wasn't sure since the PR itself changes nothing but reflects a change made earlier, but if I understand right that makes sense, thanks! I'll update the PR description.