Revert "fix project file"

This reverts commit 7cbce0e.

Author: dsyme

fcs/FSharp.Compiler.Service.Tests/FSharp.Compiler.Service.Tests.fsproj

@@ -10,6 +10,7 @@
     <TreatWarningsAsErrors>true</TreatWarningsAsErrors>
     <GenerateDocumentationFile>true</GenerateDocumentationFile>
     <OutputPath>..\..\$(Configuration.ToLower())\fcs</OutputPath>
+    <DebugType>portable</DebugType>
     <IsPackable>false</IsPackable>
     <CopyLocalLockFileAssemblies>true</CopyLocalLockFileAssemblies> <!-- Tests won't run without this, at least on OSX, see https://github.com/NuGet/Home/issues/4837#issuecomment-354536302 -->
   </PropertyGroup>