Fix visibility for views

[jackkoenig]

A latent issue with how Binding and lexical scope checking (aka visiblity) works in Chisel is that it is assumes a single "location" for a given Data. Aggregate Views can have multiple locations so this logic needs to be generalized. I started doing that work but it's a much larger overhaul than I was willing to commit to for a bug fix, so I ditched that idea and did something more focused. We do need to make that change eventually though.

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?
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• Did you add appropriate documentation in docs/src?
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• Did you add text to be included in the Release Notes for this change?

Type of Improvement

• Bugfix

Desired Merge Strategy

• Squash

Release Notes

DataMirror.isVisible and other things checking visibility now work properly for views.

Reviewer Checklist (only modified by reviewer)

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• 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)?
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