[tests] Add regression test

src/tests/JIT/Regression/JitBlue/Runtime_79354/Runtime_79354.cs

@@ -0,0 +1,45 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+using System;
+using System.Reflection;
+
+public interface IGetContents {
+    (string, int, string) GetContents();
+}
+
+public struct MyStruct : IGetContents {
+    public string s1;
+    public int a;
+    public string s2;
+
+    public (string, int, string) GetContents()
+    {
+        return (s1, a, s2);
+    }
+}
+
+public class Program {
+
+    public delegate (string, int, string) MyDelegate(IGetContents arg);
+
+    public static int Main(string[] args)
+    {
+        MyStruct str = new MyStruct();
+        str.s1 = "test1";
+        str.a = 42;
+        str.s2 = "test2";
+
+        MethodInfo mi = typeof(IGetContents).GetMethod("GetContents");
+        MyDelegate func = (MyDelegate)mi.CreateDelegate(typeof(MyDelegate));
+
+        (string c1, int c2, string c3) = func(str);
+        if (c1 != "test1")
+            return 1;
+        if (c2 != 42)
+            return 2;
+        if (c3 != "test2")
+            return 3;
+        return 100;
+    }
+}

src/tests/JIT/Regression/JitBlue/Runtime_79354/Runtime_79354.csproj

@@ -0,0 +1,9 @@
+<Project Sdk="Microsoft.NET.Sdk">
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <Optimize>True</Optimize>
+  </PropertyGroup>
+  <ItemGroup>
+    <Compile Include="$(MSBuildProjectName).cs" />
+  </ItemGroup>
+</Project>