Add test case

src/tests/JIT/Regression/JitBlue/Runtime_57912/Runtime_57912.cs

@@ -0,0 +1,43 @@
+// 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.CompilerServices;
+using System.Runtime.InteropServices;
+
+[StructLayout(LayoutKind.Sequential)]
+internal struct AA
+{
+    public short tmp1;
+    public short q;
+
+    public ushort tmp2;
+    public int tmp3;
+
+    public AA(short qq)
+    {
+        tmp1 = 106;
+        tmp2 = 107;
+        tmp3 = 108;
+        q = qq;
+    }
+
+    // The test verifies that we accurately update the byref variable that is a field of struct.
+    public static short call_target_ref(ref short arg) { arg = 100; return arg; }
+}
+
+
+public class Runtime_57912
+{
+
+    public static int Main()
+    {
+        return (int)test_0_17(100, new AA(100), new AA(0));
+    }
+
+    [MethodImpl(MethodImplOptions.NoInlining)]
+    static short test_0_17(int num, AA init, AA zero)
+    {
+        return AA.call_target_ref(ref init.q);
+    }
+}

src/tests/JIT/Regression/JitBlue/Runtime_57912/Runtime_57912.csproj

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+<Project Sdk="Microsoft.NET.Sdk">
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <Optimize>True</Optimize>
+    <DebugType>None</DebugType>
+  </PropertyGroup>
+  <ItemGroup>
+    <Compile Include="$(MSBuildProjectName).cs" />
+  </ItemGroup>
+  <PropertyGroup>
+    <CLRTestBatchPreCommands><![CDATA[
+$(CLRTestBatchPreCommands)
+set DOTNET_JitEnableFinallyCloning=0
+]]></CLRTestBatchPreCommands>
+    <BashCLRTestPreCommands><![CDATA[
+$(BashCLRTestPreCommands)
+export DOTNET_JitEnableFinallyCloning=0
+]]></BashCLRTestPreCommands>
+  </PropertyGroup>
+</Project>