JIT: Remove VNFOA_Commutative from value numbering attribute table

[Copilot]

Delete VNFOA_Commutative from the VNFOpAttrib enum and from the valuenumfuncs.h table. Instead, VNFuncIsCommutative now lists commutative functions explicitly.

Changes

valuenumfuncs.h

• Remove the commute (3rd) parameter from all ValueNumFuncDef macro invocations, changing from 4-arg to 3-arg: ValueNumFuncDef(name, arity, knownNonNull)
• Updated the header comment to reflect the new macro signature
• Removed ((flag) & HW_Flag_Commutative) >> 0 from the HARDWARE_INTRINSIC macro expansions

valuenum.h

• Removed VNFOA_Commutative from the VNFOpAttrib enum and its associated shift constant and static_assert
• Compacted the bit layout (arity now starts at bit 1, KnownNonNull at bit 4)
• Removed commute parameter from GetOpAttribsForGenTree and GetOpAttribsForFunc declarations
• Moved VNFuncIsCommutative from inline in the header to an out-of-line implementation in the .cpp (needed because HWIntrinsicInfo is not available in the header)

valuenum.cpp

• New explicit VNFuncIsCommutative implementation that:
  • genTreeOps (< VNF_Boundary): delegates to GenTree::OperIsCommutative — covers GT_ADD, GT_MUL, GT_OR, GT_XOR, GT_AND, etc.
  • VNF overflow functions: explicit switch for VNF_ADD_OVF, VNF_MUL_OVF, VNF_ADD_UN_OVF, VNF_MUL_UN_OVF
  • RISCV64 intrinsics: VNF_MinInt, VNF_MaxInt, VNF_MinInt_UN, VNF_MaxInt_UN
  • HW intrinsics: delegates to HWIntrinsicInfo::IsCommutative
• Updated GetOpAttribsForGenTree and GetOpAttribsForFunc to remove commute parameter
• Updated all ValueNumFuncDef macro expansions in initialization/validation code
• Removed the HW intrinsic commutative loop from ValidateValueNumStoreStatics

Missed commutativity check

VNF_OR/VNF_AND/VNF_XOR don't exist as VNF-range functions — these are genTreeOps (GT_OR, GT_AND, GT_XOR) handled by GenTree::OperIsCommutative. No previously-commutative functions are lost.

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