Adding System\Runtime\CompilerServices\IsByRefLikeAttribute type (#11369)

described in: https://github.com/dotnet/corefx/issues/19212

Signed-off-by: dotnet-bot-corefx-mirror <dotnet-bot@microsoft.com>

Author: VSadov

src/Common/src/CoreLib/System.Private.CoreLib.Shared.projitems

@@ -1,4 +1,4 @@
-<?xml version="1.0" encoding="utf-8"?>
+<?xml version="1.0" encoding="utf-8"?>
 <Project xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
   <PropertyGroup>
     <MSBuildAllProjects>$(MSBuildAllProjects);$(MSBuildThisFileFullPath)</MSBuildAllProjects>
@@ -284,6 +284,7 @@
     <Compile Include="$(MSBuildThisFileDirectory)System\Runtime\CompilerServices\INotifyCompletion.cs"/>
     <Compile Include="$(MSBuildThisFileDirectory)System\Runtime\CompilerServices\InternalsVisibleToAttribute.cs"/>
     <Compile Include="$(MSBuildThisFileDirectory)System\Runtime\CompilerServices\IsConst.cs"/>
+    <Compile Include="$(MSBuildThisFileDirectory)System\Runtime\CompilerServices\IsByRefLikeAttribute.cs"/>
     <Compile Include="$(MSBuildThisFileDirectory)System\Runtime\CompilerServices\IsVolatile.cs"/>
     <Compile Include="$(MSBuildThisFileDirectory)System\Runtime\CompilerServices\IteratorStateMachineAttribute.cs"/>
     <Compile Include="$(MSBuildThisFileDirectory)System\Runtime\CompilerServices\ITuple.cs"/>

src/Common/src/CoreLib/System/Runtime/CompilerServices/IsByRefLikeAttribute.cs

@@ -0,0 +1,21 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+using System.ComponentModel;
+
+namespace System.Runtime.CompilerServices
+{
+    /// <summary>
+    /// Reserved to be used by the compiler for tracking metadata.
+    /// This attribute should not be used by developers in source code.
+    /// </summary>
+    [EditorBrowsable(EditorBrowsableState.Never)]
+    [AttributeUsage(AttributeTargets.Struct)]
+    public sealed class IsByRefLikeAttribute : Attribute
+    {
+        public IsByRefLikeAttribute()
+        {
+        }
+    }
+}