add test case

src/tests/JIT/Regression/JitBlue/Runtime_75828/Runtime_75828.cs

@@ -0,0 +1,30 @@
+// 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.Runtime.InteropServices;
+
+// Verify that the Jit_Patchpoint helper inserted for OSR preserves last error
+
+class Runtime_75828
+{
+    public static int Main()
+    {
+        Marshal.SetLastSystemError(42);
+
+        int expected = 5_000_000 + 42;
+
+        int result = 0;
+        for (int i = 0; i < 10_000_000; i++)
+        {
+            result += i % 2;
+        }
+
+        result += Marshal.GetLastSystemError();
+
+        Console.WriteLine($"got {result} expected {expected}");
+
+        return result == expected ? 100 : -1;
+    }
+}
+

src/tests/JIT/Regression/JitBlue/Runtime_75828/Runtime_75828.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>