Removed un-needed test CS file, added comment

Author: XAML-Knight

UITests/UITests.App/UITests.App.csproj

@@ -231,10 +231,6 @@
       <Project>{84ab7dc5-95c9-4cf8-a370-d077e9e9ef1a}</Project>
       <Name>Microsoft.Toolkit.Uwp.UI.Controls.Primitives</Name>
     </ProjectReference>
-    <ProjectReference Include="..\..\Microsoft.Toolkit.Uwp.UI.Controls\Microsoft.Toolkit.Uwp.UI.Controls.csproj">
-      <Project>{099b60fd-dad6-4648-9de2-8dbf9dcd9557}</Project>
-      <Name>Microsoft.Toolkit.Uwp.UI.Controls</Name>
-    </ProjectReference>
     <ProjectReference Include="..\..\Microsoft.Toolkit.Uwp.UI.Media\Microsoft.Toolkit.Uwp.UI.Media.csproj">
       <Project>{75f9ee44-3efa-47bc-aedd-351b9834a0af}</Project>
       <Name>Microsoft.Toolkit.Uwp.UI.Media</Name>

UITests/UITests.Tests.Shared/Controls/ConstrainedBoxTest.cs

@@ -6,6 +6,8 @@
       xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
       Background="{ThemeResource ApplicationPageBackgroundThemeBrush}"
       mc:Ignorable="d">
+    <!--  Merely binding the AspectRatio to an integer, here, is enough for a valid test
+        of implicit operator for int -->
     <controls:ConstrainedBox x:Name="ConstrainedBox"
                              Height="100"
                              AspectRatio="{x:Bind IntegerWidth}">