make host app target netfx / nca 2.0

src/tools/Avalonia.Designer.HostApp/Avalonia.Designer.HostApp.csproj

@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
   <PropertyGroup>
     <OutputType>Exe</OutputType>
-    <TargetFrameworks>netstandard2.1</TargetFrameworks>
+    <TargetFrameworks>net461;netcoreapp2.0</TargetFrameworks>
   </PropertyGroup>
   <!--Disable Net Perf. analyzer for submodule to avoid commit issue -->
   <PropertyGroup>

tests/Avalonia.DesignerSupport.Tests/DesignerSupportTests.cs

@@ -19,7 +19,7 @@ namespace Avalonia.DesignerSupport.Tests
 {
     public class DesignerSupportTests
     {
-        private const string DesignerAppPath = "../../../../../src/tools/Avalonia.Designer.HostApp/bin/$BUILD/netstandard2.1/Avalonia.Designer.HostApp.dll";
+        private const string DesignerAppPath = "../../../../../src/tools/Avalonia.Designer.HostApp/bin/$BUILD/netcoreapp2.0/Avalonia.Designer.HostApp.dll";
         private readonly Xunit.Abstractions.ITestOutputHelper outputHelper;
 
         public DesignerSupportTests(Xunit.Abstractions.ITestOutputHelper outputHelper)