Return scalar MulMod results and benchmark native reducers

EvenPerfectBitScanner.Benchmarks/GpuUInt128NativeModuloBenchmarks.cs

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+using System.Collections.Generic;
+using BenchmarkDotNet.Attributes;
+using BenchmarkDotNet.Jobs;
+using PerfectNumbers.Core.Gpu;
+
+namespace EvenPerfectBitScanner.Benchmarks;
+
+[SimpleJob(RuntimeMoniker.Net80)]
+[MemoryDiagnoser]
+public class GpuUInt128NativeModuloBenchmarks
+{
+    private static readonly NativeModuloInput[] Inputs = new NativeModuloInput[]
+    {
+        new(0x0000_0000_0000_0003UL, 0x0000_0000_0000_0005UL, 0x0000_0000_0000_007FUL, "TinyOperands"),
+        new(0x7FFF_FFFF_FFFF_FFC3UL, 0x7FFF_FFFF_FFFF_FF21UL, 0x7FFF_FFFF_FFFF_FFC5UL, "NearModulus"),
+        new(0xFFFF_FFFF_FFFF_FFFBUL, 0xFFFF_FFFF_FFFF_FFCFUL, 0xFFFF_FFFF_FFFF_FFF5UL, "DenseOperands"),
+        new(0x0123_4567_89AB_CDEFUL, 0x0FED_CBA9_8765_4321UL, 0x1FFF_FFFF_FFFF_FFFBUL, "MixedMagnitude"),
+    };
+
+    [ParamsSource(nameof(GetInputs))]
+    public NativeModuloInput Input { get; set; }
+
+    public static IEnumerable<NativeModuloInput> GetInputs() => Inputs;
+
+    [Benchmark(Baseline = true)]
+    public ulong ImmediateModulo()
+    {
+        GpuUInt128 state = new(Input.Left % Input.Modulus);
+        return state.MulMod(Input.Right, Input.Modulus);
+    }
+
+    [Benchmark]
+    public ulong DeferredNativeModulo()
+    {
+        GpuUInt128 state = new(Input.Left);
+        return state.MulModWithNativeModulo(Input.Right, Input.Modulus);
+    }
+
+    public readonly record struct NativeModuloInput(ulong Left, ulong Right, ulong Modulus, string Name)
+    {
+        public override string ToString() => Name;
+    }
+}