Add test for non-async generic methods mismatch in ILC scanner/JIT

src/tests/async/awaitingnoasyncgeneric/awaitingnoasyncgeneric.cs

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+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+using System.Runtime.CompilerServices;
+using System.Threading.Tasks;
+using Xunit;
+
+public class AwaitingNoAsyncGeneric
+{
+    [Fact]
+    public static void TestEntryPoint()
+    {
+        Assert.Equal("hello", new Caller<string>().RunAsync("hello").GetAwaiter().GetResult());
+        Assert.Equal(42, new Caller<int>().RunAsync(42).GetAwaiter().GetResult());
+    }
+}
+
+public class Caller<T>
+{
+    [MethodImpl(MethodImplOptions.NoInlining)]
+    public async ValueTask<T> RunAsync(T value)
+    {
+        return await Helper.GetValueAsync(value).ConfigureAwait(false);
+    }
+}
+
+public static class Helper
+{
+    // Non-async method returning ValueTask<T>, so the compiler does not emit
+    // MethodImplAttributes.Async. This is the condition that can trigger a
+    // scanner/JIT mismatch.
+    [MethodImpl(MethodImplOptions.NoInlining)]
+    public static ValueTask<T> GetValueAsync<T>(T value)
+    {
+        return new ValueTask<T>(value);
+    }
+}

src/tests/async/awaitingnoasyncgeneric/awaitingnoasyncgeneric.csproj

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+<Project Sdk="Microsoft.NET.Sdk.IL">
+  <PropertyGroup>
+      <!-- https://github.com/dotnet/runtime/issues/127179 -->
+      <NativeAotIncompatible>true</NativeAotIncompatible>
+      <!-- Needed due to NativeAotIncompatible -->
+      <RequiresProcessIsolation>true</RequiresProcessIsolation>
+  </PropertyGroup>
+  <ItemGroup>
+    <Compile Include="$(MSBuildProjectName).cs" />
+  </ItemGroup>
+</Project>