Remove leftover csproj reference to already removed project in test project PowerShellEditorServices.Test.Host.csproj (#1298)

* Fix csproj reference in test project PowerShellEditorServices.Test.Host.csproj

* remove reference

Author: bergmeister

test/PowerShellEditorServices.Test.Host/PowerShellEditorServices.Test.Host.csproj

@@ -11,7 +11,6 @@
   </ItemGroup>
   <ItemGroup>
     <ProjectReference Include="..\..\src\PowerShellEditorServices\PowerShellEditorServices.csproj" />
-    <ProjectReference Include="..\..\src\PowerShellEditorServices.Host\PowerShellEditorServices.Host.csproj" />
     <ProjectReference Include="..\PowerShellEditorServices.Test.Shared\PowerShellEditorServices.Test.Shared.csproj" />
   </ItemGroup>
   <PropertyGroup Condition=" '$(TargetFramework)' == 'netcoreapp2.1' ">