Remove reference includes on netstandard

src/TestData/TestData-2017.csproj

@@ -1,6 +1,6 @@
 <Project Sdk="Microsoft.NET.Sdk">
     <PropertyGroup>
-        <TargetFrameworks>net35;netstandard1.0</TargetFrameworks>
+        <TargetFrameworks>net35;netstandard1.1</TargetFrameworks>
         <GenerateAssemblyInfo>false</GenerateAssemblyInfo>
         <AssemblyName>MathNet.Numerics.TestData</AssemblyName>
         <RootNamespace>MathNet.Numerics.TestData</RootNamespace>
@@ -53,7 +53,7 @@
     <PropertyGroup Condition="'$(TargetFramework)'=='netstandard1.1'">
         <DefineConstants>NETSTANDARD</DefineConstants>
     </PropertyGroup>
-    <ItemGroup>
+    <ItemGroup Condition="'$(TargetFramework)' != 'netstandard1.1'">
         <Reference Include="System" />
         <Reference Include="System.Core" />
         <Reference Include="System.Xml.Linq" />