Use netcoreapp implementations on netstd2.1 where applicable

Author: mattjohnsonpint

src/Microsoft.Data.SqlClient/netcore/src/Microsoft.Data.SqlClient.csproj

@@ -514,13 +514,6 @@
       <Link>Microsoft\Data\SqlClient\SqlEnclaveAttestationParameters.NotSupported.cs</Link>
     </Compile>
   </ItemGroup>
-  <ItemGroup Condition="'$(OSGroup)' != 'AnyOS' AND '$(TargetGroup)' == 'netstandard'">
-    <Compile Include="Microsoft\Data\SqlClient\SNI\SNIStreams.Task.cs" />    
-    <Compile Include="Microsoft\Data\SqlClient\SNI\SslOverTdsStream.NetStandard.cs" />
-    <Compile Include="Microsoft\Data\SqlClient\SqlAuthenticationProviderManager.NetStandard.cs" />
-    <Compile Include="Microsoft\Data\SqlClient\SqlDelegatedTransaction.NetStandard.cs" />
-    <Compile Include="Microsoft\Data\SqlClient\TdsParser.NetStandard.cs" />
-  </ItemGroup>
   <ItemGroup Condition="'$(OSGroup)' != 'AnyOS' AND '$(TargetFramework)' != 'netstandard2.0'">
     <Compile Include="..\..\src\Microsoft\Data\SqlClient\AlwaysEncryptedEnclaveProviderUtils.cs">
       <Link>Microsoft\Data\SqlClient\AlwaysEncryptedEnclaveProviderUtils.cs</Link>
@@ -549,24 +542,28 @@
     <Compile Include="..\..\src\Microsoft\Data\SqlClient\VirtualSecureModeEnclaveProviderBase.cs">
       <Link>Microsoft\Data\SqlClient\VirtualSecureModeEnclaveProviderBase.cs</Link>
     </Compile>
+    <Compile Include="Microsoft\Data\SqlClient\SNI\SNIStreams.ValueTask.cs" />
+    <Compile Include="Microsoft\Data\SqlClient\SNI\SslOverTdsStream.NetCoreApp.cs" />
     <Compile Include="Microsoft\Data\SqlClient\AlwaysEncryptedKeyConverter.CrossPlatform.cs" />
+    <Compile Include="Microsoft\Data\SqlClient\SqlAuthenticationProviderManager.NetCoreApp.cs" />
+    <Compile Include="Microsoft\Data\SqlClient\SqlClientEventSource.NetCoreApp.cs" />
     <Compile Include="Microsoft\Data\SqlClient\SqlColumnEncryptionEnclaveProvider.NetCoreApp.cs" />
+    <Compile Include="Microsoft\Data\SqlClient\SqlDelegatedTransaction.NetCoreApp.cs" />
+    <Compile Include="Microsoft\Data\SqlClient\TdsParser.NetCoreApp.cs" />
   </ItemGroup>
-  <!-- netstandard 2.1 and above -->
-  <ItemGroup Condition="'$(OSGroup)' != 'AnyOS' AND '$(TargetFramework)' != 'netstandard2.0'">
-    <Compile Include="Microsoft\Data\SqlClient\SqlClientEventSource.NetCoreApp.cs" />
+  <ItemGroup Condition="'$(OSGroup)' != 'AnyOS' AND '$(TargetFramework)' == 'netstandard2.0'">
+    <Compile Include="Microsoft\Data\SqlClient\SNI\SNIStreams.Task.cs" />    
+    <Compile Include="Microsoft\Data\SqlClient\SNI\SslOverTdsStream.NetStandard.cs" />
+    <Compile Include="Microsoft\Data\SqlClient\SqlAuthenticationProviderManager.NetStandard.cs" />
+    <Compile Include="Microsoft\Data\SqlClient\SqlDelegatedTransaction.NetStandard.cs" />
+    <Compile Include="Microsoft\Data\SqlClient\TdsParser.NetStandard.cs" />
   </ItemGroup>
   <ItemGroup Condition="'$(OSGroup)' != 'AnyOS' AND '$(TargetGroup)' == 'netcoreapp'">
     <Compile Include="..\..\src\Microsoft\Data\SqlClient\SqlDependencyUtils.AssemblyLoadContext.cs">
       <Link>Microsoft\Data\SqlClient\SqlDependencyUtils.AssemblyLoadContext.cs</Link>
     </Compile>
     <Compile Include="Microsoft\Data\ProviderBase\DbConnectionPool.NetCoreApp.cs" />
-    <Compile Include="Microsoft\Data\SqlClient\SNI\SNIStreams.ValueTask.cs" />
-    <Compile Include="Microsoft\Data\SqlClient\SNI\SslOverTdsStream.NetCoreApp.cs" />
-    <Compile Include="Microsoft\Data\SqlClient\SqlAuthenticationProviderManager.NetCoreApp.cs" />
-    <Compile Include="Microsoft\Data\SqlClient\SqlConnectionFactory.AssemblyLoadContext.cs" />    
-    <Compile Include="Microsoft\Data\SqlClient\SqlDelegatedTransaction.NetCoreApp.cs" />
-    <Compile Include="Microsoft\Data\SqlClient\TdsParser.NetCoreApp.cs" />
+    <Compile Include="Microsoft\Data\SqlClient\SqlConnectionFactory.AssemblyLoadContext.cs" />
   </ItemGroup>
   <ItemGroup Condition="'$(OSGroup)' != 'AnyOS'">
     <Compile Include="Resources\StringsHelper.cs">