Kept only the most recent unit tests which are sufficient for both netcoreapp and netstandard

Author: briancylui

test/Microsoft.ML.CpuMath.UnitTests.netcoreapp/UnitTests.netcoreapp.cs renamed to test/Microsoft.ML.CpuMath.UnitTests.netcoreapp/UnitTests.cs

@@ -12,5 +12,9 @@
   <ItemGroup>
     <NativeAssemblyReference Include="CpuMathNative" />
   </ItemGroup>
+
+  <ItemGroup>
+    <Compile Include="..\Microsoft.ML.CpuMath.UnitTests.netcoreapp\UnitTests.cs" />
+  </ItemGroup>
 
-</Project>
+</Project>