DRAFT: Createwhile write after read

[dhartglassMSFT]

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[Copilot]

Pull request overview

Adds the SVE2 CreateWhileWriteAfterReadMask* (WHILEWR) intrinsic family alongside the existing CreateWhileReadAfterWriteMask* (WHILERW) family, and extends the shared test template to cover both, including a new "reverse offset by one" scenario that exercises the asymmetric behavior between the two instructions.

Changes:

• Adds 10 new CreateWhileWriteAfterReadMask{Type} public APIs (Sve2) in ref assembly, the throwing PlatformNotSupported stubs, and the recursive forwarding stubs in Sve2.cs.
• Wires up the new intrinsics in hwintrinsiclistarm64sve.h (mapping each base type to INS_sve_whilewr) and extends the EA_8BYTE pointer-operand codegen case in hwintrinsiccodegenarm64.cpp to cover the new IDs.
• Renames the shared SVE RW test template to SveCreateWhileDependencyMaskTest, parameterizes it with IsWriteAfterRead, adds a RunReverseOffsetByOneScenario distinguishing WHILEWR vs WHILERW, and adds 10 generator entries for the new WHILEWR tests.

Reviewed changes

Copilot reviewed 8 out of 8 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
src/libraries/System.Runtime.Intrinsics/ref/System.Runtime.Intrinsics.cs	Adds 10 new ref APIs for CreateWhileWriteAfterReadMask*.
src/libraries/System.Private.CoreLib/src/System/Runtime/Intrinsics/Arm/Sve2.PlatformNotSupported.cs	Adds throwing stubs and XML docs for the new intrinsics.
src/libraries/System.Private.CoreLib/src/System/Runtime/Intrinsics/Arm/Sve2.cs	Adds the runtime intrinsic forwarding entry points.
src/coreclr/jit/hwintrinsiclistarm64sve.h	Registers the 10 new intrinsic IDs mapped to INS_sve_whilewr per base type.
src/coreclr/jit/hwintrinsiccodegenarm64.cpp	Routes the new IDs through the existing 64-bit pointer codegen path (comment updated to WHILERW/WHILEWR).
src/tests/Common/GenerateHWIntrinsicTests/Arm/Templates.cs	Renames the template config to SveCreateWhileDependencyMaskTest.
src/tests/Common/GenerateHWIntrinsicTests/Arm/Sve2Tests.cs	Updates RW entries with IsWriteAfterRead=false and adds 10 WHILEWR entries with IsWriteAfterRead=true.
src/tests/JIT/HardwareIntrinsics/Arm/Shared/SveCreateWhileDependencyMaskTest.template	Renames the test class, adds RunReverseOffsetByOneScenario, and documents the WHILEWR/WHILERW spec semantics.