Fix missing zero-offset sequences and add checking

[SingleAccretion]

A couple changes:

1. Add a checker which ensures we do not forget to call ExtendPtrVN (or equivalent) when necessary.
2. Fix missing zero-offset sequences for ADDR(LCL_VAR) (no tests because reproducing bad codegen for this issue is "hard", and the checker asserts anyway).
3. Fix missing NotAField zero-offset sequences. These are important to preserve because they carry the fact we could have had an overlapping field in the sequence. Tests added.
4. Some printing enhancements for NotAField sequences, to make the dumps more informative.

Ref: #64773.

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Issue Details

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Namely, that we don't forget to call ExtendPtrVN when necessary. This would have, for example, caught the problem being fixed in #64501.

Ref: #64773.

No diffs are expected.

Author:	SingleAccretion
Assignees:	-
Labels:	area-CodeGen-coreclr
Milestone:	-

[SingleAccretion]

There is a typo in this change, but the proper version found two cases where we miss field sequences. So we'll leave this in the draft state until fixes land.

[SingleAccretion]

This is now blocked on #64501.

Edit: no more.

[SingleAccretion]

Will assume OSX timeouts are not related (happening everywhere currently...).

Diffs are cases where we were numbering a real-world array of StructWithOverlappingFields (presumably, not in a way that lead to silent bad codegen).

@dotnet/jit-contrib

[jakobbotsch]

/azp run Antigen, Fuzzlyn

[azure-pipelines]

Azure Pipelines successfully started running 2 pipeline(s).

[jakobbotsch]

@SingleAccretion It looks like the fuzzlyn run hit an assert that was changed in #65387, can you investigate?

[jakobbotsch]

LGTM, thanks!

[SingleAccretion]

can you investigate?

Yes, of course.

[jakobbotsch]

I believe Fuzzlyn/Antigen failures are preexisting.