Enable multi-reg LONG nodes on 32 bit

[SingleAccretion]

Or, rather, enable promotion of multi-reg LONG variables, unblocking field enregistration.

The diffs (x86) are nice and simple:

- mov dword ptr [esp], eax- mov dword ptr [esp+04H], edx- mov eax, dword ptr [esp]- mov edx, dword ptr [esp+04H]
add eax, -1
adc edx, -1

And also numerous (-35K for the benchmarks collection on x86).

[ghost]

Tagging subscribers to this area: @JulieLeeMSFT, @jakobbotsch
See info in area-owners.md if you want to be subscribed.

Issue Details

---

Or, rather, enable promotion of multi-reg LONG variables, unblocking field enregistration.

The diffs are nice and simple:

- mov dword ptr [esp], eax- mov dword ptr [esp+04H], edx- mov eax, dword ptr [esp]- mov edx, dword ptr [esp+04H]
add eax, -1
adc edx, -1

And also numerous (-35K for the benchmarks collection on x86).

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

[SingleAccretion]

@dotnet/jit-contrib

[AndyAyersMS]

@TIHan perhaps you can review this one?

[kunalspathak]

A nit comment and a question.

[kunalspathak]

I am not able to see arm Release failures. Tried rerunning the jobs, but they are not getting scheduled. Do you remember what the failure was?

[SingleAccretion]

No, unfortunately... Let's rerun the whole CI to get fresher coverage.

[SingleAccretion]

GH doesn't show it, but Libraries Build arm Release succeeded: https://dev.azure.com/dnceng-public/public/_build/results?buildId=61503&view=logs&j=fbba4562-0196-5144-0bc8-97e5ecde48bd.