Fix compile assembly on netfx for crypto-xml (#19422)

* fix compile assembly on netfx for crypto-xml

* Add refs

Author: krwq

src/System.Security.Cryptography.Xml/ref/Configurations.props

@@ -2,7 +2,8 @@
 <Project ToolsVersion="14.0" DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
   <PropertyGroup>
     <BuildConfigurations>
-      netstandard
+      netstandard;
+      netfx
     </BuildConfigurations>
   </PropertyGroup>
 </Project>

src/System.Security.Cryptography.Xml/ref/System.Security.Cryptography.Xml.csproj

@@ -3,9 +3,17 @@
   <Import Project="$([MSBuild]::GetDirectoryNameOfFileAbove($(MSBuildThisFileDirectory), dir.props))\dir.props" />
   <PropertyGroup>
     <ProjectGuid>{C7266957-DB20-4250-9C2E-E1FF83EDBD71}</ProjectGuid>
+    <IsPartialFacadeAssembly Condition="'$(TargetGroup)' == 'netfx'">true</IsPartialFacadeAssembly>
   </PropertyGroup>
   <PropertyGroup Condition="'$(Configuration)|$(Platform)' == 'netstandard-Debug|AnyCPU'" />
   <PropertyGroup Condition="'$(Configuration)|$(Platform)' == 'netstandard-Release|AnyCPU'" />
+  <ItemGroup Condition="'$(IsPartialFacadeAssembly)'  == 'true'">
+    <Reference Include="mscorlib" />
+    <Reference Include="System" />
+    <Reference Include="System.Core" />
+    <Reference Include="System.Xml" />
+    <Reference Include="System.Security" />
+  </ItemGroup>
   <ItemGroup>
     <Compile Include="System.Security.Cryptography.Xml.cs" />
   </ItemGroup>