Remove SkiaSharp package from test project

tests/Avalonia.RenderTests/Avalonia.Skia.RenderTests.csproj

@@ -55,10 +55,6 @@
       <HintPath>..\..\packages\Magick.NET-Q16-AnyCPU.7.0.0.0101\lib\net40-client\Magick.NET-Q16-AnyCPU.dll</HintPath>
       <Private>True</Private>
     </Reference>
-    <Reference Include="SkiaSharp, Version=1.54.0.0, Culture=neutral, PublicKeyToken=0738eb9f132ed756, processorArchitecture=MSIL">
-      <HintPath>..\..\packages\SkiaSharp.1.54.1\lib\net45\SkiaSharp.dll</HintPath>
-      <Private>True</Private>
-    </Reference>
     <Reference Include="System" />
     <Reference Include="System.Core" />
     <Reference Include="System.Xml.Linq" />
@@ -141,9 +137,7 @@
       <ErrorText>This project references NuGet package(s) that are missing on this computer. Use NuGet Package Restore to download them.  For more information, see http://go.microsoft.com/fwlink/?LinkID=322105. The missing file is {0}.</ErrorText>
     </PropertyGroup>
     <Error Condition="!Exists('..\..\packages\xunit.runner.visualstudio.2.1.0\build\net20\xunit.runner.visualstudio.props')" Text="$([System.String]::Format('$(ErrorText)', '..\..\packages\xunit.runner.visualstudio.2.1.0\build\net20\xunit.runner.visualstudio.props'))" />
-    <Error Condition="!Exists('..\..\packages\SkiaSharp.1.54.1\build\net45\SkiaSharp.targets')" Text="$([System.String]::Format('$(ErrorText)', '..\..\packages\SkiaSharp.1.54.1\build\net45\SkiaSharp.targets'))" />
   </Target>
-  <Import Project="..\..\packages\SkiaSharp.1.54.1\build\net45\SkiaSharp.targets" Condition="Exists('..\..\packages\SkiaSharp.1.54.1\build\net45\SkiaSharp.targets')" />
   <!-- To modify your build process, add your task inside one of the targets below and uncomment it. 
        Other similar extension points exist, see Microsoft.Common.targets.
   <Target Name="BeforeBuild">

tests/Avalonia.RenderTests/packages.Avalonia.Skia.RenderTests.config

@@ -1,7 +1,6 @@
 <?xml version="1.0" encoding="utf-8"?>
 <packages>
   <package id="Magick.NET-Q16-AnyCPU" version="7.0.0.0101" targetFramework="net45" />
-  <package id="SkiaSharp" version="1.54.1" targetFramework="net45" />
   <package id="xunit" version="2.1.0" targetFramework="net45" />
   <package id="xunit.abstractions" version="2.0.0" targetFramework="net45" />
   <package id="xunit.assert" version="2.1.0" targetFramework="net45" />