Support $(Platform) condition references?

[kirsan31]

Hi. If csproj contains $(Platform) condition references like:

  <!-- x86 specific referneces -->
  <ItemGroup Condition=" '$(Platform)' == 'x86' ">
    <Reference Include="lib">
      <HintPath>..\tstlib\lib.dll</HintPath>
    </Reference>
    <!-- any additional x86 specific references -->
  </ItemGroup>
  <!-- x64 specific referneces -->
  <ItemGroup Condition=" '$(Platform)' == 'x64' ">
    <Reference Include="lib64">
      <HintPath>..\tstlib\lib64.dll</HintPath>
    </Reference>
    <!-- any additional x64 specific references -->
  </ItemGroup>

then tool will fail with:

System.Collections.Generic.KeyNotFoundException: The given key was not present in the dictionary.
   at System.Collections.Immutable.ImmutableDictionary`2.get_Item(TKey key)
   at MSBuild.Conversion.Project.ProjectRootElementExtensions.RemoveOrUpdateItems(IProjectRootElement projectRootElement, ImmutableDictionary`2 differs, BaselineProject baselineProject, String tfm) in /_/src/MSBuild.Conversion.Project/ProjectRootElementExtensions.cs:line 195
   at MSBuild.Conversion.Project.Converter.ConvertProjectFile() in /_/src/MSBuild.Conversion.Project/Converter.cs:line 69
   at MSBuild.Conversion.Project.Converter.Convert(String outputPath) in /_/src/MSBuild.Conversion.Project/Converter.cs:line 28
   at MSBuild.Conversion.Program.Run(String project, String workspace, String msbuildPath, Boolean diffOnly, Boolean noBackup) in /_/src/try-convert/Program.cs:line 85

But such, condition references work well in .NET Core too. So, I think try-convert need to transfer them as is...