Remove reference codecs and simplify tests

Author: JimBobSquarePants

tests/Directory.Build.targets

@@ -19,11 +19,6 @@
   <ItemGroup>
     <!-- Test Dependencies -->
     <PackageReference Update="BenchmarkDotNet" Version="0.13.1" />
-    <!--
-    Do not update to 14+ yet. There's differnce in how the BMP decoder handles rounding in 16 bit images.
-    See https://github.com/ImageMagick/ImageMagick/commit/27a0a9c37f18af9c8d823a3ea076f600843b553c
-    -->
-    <PackageReference Update="Magick.NET-Q16-AnyCPU" Version="13.10.0" />
     <PackageReference Update="Microsoft.DotNet.RemoteExecutor" Version="8.0.0-beta.23580.1" />
     <PackageReference Update="Microsoft.DotNet.XUnitExtensions" Version="8.0.0-beta.23580.1" />
     <PackageReference Update="Moq" Version="4.20.72" />

tests/ImageSharp.Drawing.Tests/ImageSharp.Drawing.Tests.csproj

@@ -24,12 +24,9 @@
   </Choose>
 
   <ItemGroup>
-    <PackageReference Include="Magick.NET-Q16-AnyCPU" />
     <PackageReference Include="Microsoft.DotNet.RemoteExecutor" />
     <PackageReference Include="Microsoft.DotNet.XUnitExtensions" />
     <PackageReference Include="Moq" />
-    <PackageReference Include="runtime.osx.10.10-x64.CoreCompat.System.Drawing" Condition="'$(IsOSX)'=='true'" />
-    <PackageReference Include="System.Drawing.Common" />
     <PackageReference Include="GeoJSON.Net" />
     <PackageReference Include="Silk.NET.WebGPU" Version="2.23.0" />
     <PackageReference Include="Silk.NET.WebGPU.Extensions.WGPU" Version="2.23.0" />