Remove duplicated SVE GatherVector APIs

[ylpoonlg]

These APIs are duplicated with the normal GatherVector methods, as 32-bit values doesn't need to be extended to 32-bit.

See #103370, which removed the Int32 extensions, but did not remove the UInt32 extensions.

@dotnet/arm64-contrib @a74nh

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[a74nh]

Given this is removing released APIs, I think this might need a API break issue raised against it?

[tannergooding]

Given this is removing released APIs, I think this might need a API break issue raised against it?

All the APIs are [Experimental] so they aren't "released" and we don't strictly need a breaking change doc.

I don't have a preference if we want to have a general callout for all the fixes we've made in .NET 11 to the experimental surface or not, will leave that up to everyone else.

[stephentoub]

Code Review: PR #124033 - Remove duplicated SVE GatherVector APIs

Holistic Assessment

Motivation: This PR removes duplicated SVE GatherVectorUInt32 API overloads. The removed APIs that operate on 32-bit values (Vector/Vector) are semantically equivalent to the regular GatherVector methods since 32-bit values don't need to be "zero-extended to 32-bit" - they're already 32-bit. PR #103370 previously removed the Int32 versions, but the UInt32 versions were missed.

Approach: The PR:

1. Removes redundant API overloads from Sve.cs and Sve.PlatformNotSupported.cs
2. Updates the reference assembly (System.Runtime.Intrinsics.cs)
3. Updates the JIT intrinsic table (hwintrinsiclistarm64sve.h) to only enable instructions for 64-bit types
4. Adds API compatibility suppressions for the breaking change (CP0002)
5. Removes corresponding test cases

Net positive: ✅ Yes - this is a necessary API cleanup to remove semantically incorrect/duplicate APIs, following the precedent set in #103370.

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Detailed Findings

✅ API Removals (Sve.cs, Sve.PlatformNotSupported.cs, System.Runtime.Intrinsics.cs)

• Correctly removes 16 overloads (4 methods × 4 overloads each) with Vector<int> or Vector<uint> as the return type
• Retains the 64-bit variants (Vector<long>, Vector<ulong>) which are semantically correct
• Parallel removals in both the implementation and PlatformNotSupported stub files

✅ JIT Intrinsic Table Changes (hwintrinsiclistarm64sve.h)

• Changes INS_sve_ld1w and INS_sve_ldff1w entries from supporting int/uint positions to INS_invalid
• This correctly restricts the 4 affected intrinsics to only long/ulong types

✅ API Compatibility Baseline (ApiCompatBaseline.NetCoreAppLatestStable.xml)

• All 16 removed API suppressions are correctly added with CP0002 diagnostic IDs
• Left/Right versions (net10.0 → net11.0) are correct for this .NET 11 timeframe

✅ Test Removals (SveTests.cs)

• Removes test cases for the removed APIs, keeping tests for the retained 64-bit variants

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Summary

Verdict: ✅ Approve

This PR is a clean follow-up to #103370 that removes the remaining incorrectly-designed UInt32 "zero-extend" gather APIs. The change is breaking but correctly suppressed via the API compatibility baseline. All files are consistently updated and the approach matches the prior art.

No issues found.