Fold all local addresses in local morph

[SingleAccretion]

This change enables folding for all local address trees in local morph. This is a requirement for the next round of simplifications enabled by the ADDR work (e. g. #78246 depends on this).

There is some amount of (mostly positive) diffs due to more forward substitutions enabled by the fact LCL_ADDR nodes by themselves do not need GLOB_REF. Some regressions in tests due to a bit more GLOB_REFing for "wide" indirs. One case in a huge test method where swapping LCL_VAR and LCL_VAR_ADDR operands for a relop leads us to miss out on a lot of mov suppression.

There is also a very nice TP win, up to 1% reduction in instructions retired.

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Issue Details

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This change enables folding for all local address trees in morph. This is a requirement for the next round of simplifications enabled by the ADDR work.

There is some amount of (mostly positive) diffs due to more forward substitutions enabled by the fact LCL_ADDR nodes by themselves do not need GLOB_REF.

Author:	SingleAccretion
Assignees:	-
Labels:	area-CodeGen-coreclr, community-contribution
Milestone:	-

[SingleAccretion]

@dotnet/jit-contrib

@jakobbotsch This should solve the problem of return buffer calls not having defined address shape before morph.

[BruceForstall]

fyi, I reran the diffs/replay pipelines because they failed due to missing osx-arm64 MCH files. There should be some there now (but we're still missing libraries-pmi, which failed during collection)

[jakobbotsch]

Looks great to me! I will run some stress jobs.

[jakobbotsch]

/azp run runtime-coreclr jitstress, runtime-coreclr libraries-jitstress, Fuzzlyn

[azure-pipelines]

Azure Pipelines successfully started running 3 pipeline(s).

[SingleAccretion]

Stress failures so far: #78898, #58699 (present in the run just before the current one as well).

Libraries stress failures: comparison point is https://dev.azure.com/dnceng-public/public/_build/results?buildId=102920&view=results (the previous run), Number_AsCollectionElement_RoundTrip & System.Collections.Generic.Tests.EqualityComparerTests failed there too.