Refactoring the ARM intrinsics to match API review and share code with x86 (#25508)

Refactoring the ARM intrinsics to match API review and share code with x86 (#25508)

* Rewriting the ARM64 HWIntrinsic JIT infrastructure to share with and mirror the x86 infrastructure where possible.

* Lowercasing the hwintrinsicarm64 and hwintrinsiclistarm64 files.

* Applying formatting patch.

* Fixing up some names in the PAL and VM that were missed.

* Adding support for AdvSimd.Add

* Ensure impSpecialIntrinsic returns nullptr for unsupported base types.

* Rewording various method headers and simplifying some code.

* Fixing getEmitter to GetEmitter

* Adding support for the ld1 instruction

* Applying formatting patch

* Clarifying a todo comment and removing a stray newline

* Fixing the Arm64 impSpecialIntrinsic to not assert for helper intrinsics

* Fixing some intrinsic signatures that were incorrect

* Adding the initial template files for generating Arm HWIntrinsic tests

* Generating the initial batch of Arm HWIntrinsic tests

* Replace gtRegNum with GetRegNum()

* Fixing the test template alignment checks for Arm

* Regenerating the Arm HWIntrinsic tests

* Fixing the namespace checked for Arm intrinsics

* Changing Base to ArmBase and fixing some Arm hwintrinsic metadata

* Fixing the arm emitter and lowering to not assert for hwintrinsics

* Fixing the arm intrinsics to not set the number of vector elements for SIMDScalar intrinsics

* Updating the AdvSimd.Abs tests to use negative input values

* Regenerating the arm hwintrinsic tests

* Fixing the arm hwintrinsic codegen to use the element size for simd scalar operations.

* Fixing the arm scalar intrinsic tests to check for 0 on upper bits

* Regenerating the ARM intrinsic tests

* Fixing AdvSimd.AbsScalar and AdvSimd.AddScalar to be recursive

* Marking AdvSimd.Arm64 and ArmBase.Arm64 as implemented

* Ensure that AdvSimd.Arm64.Abs is marked as variable size

Signed-off-by: dotnet-bot <dotnet-bot@microsoft.com>