Vector4<T> (dotnet#3)

* Vector4<T>

* Rvw

Author: Perksey

src/libraries/System.Private.CoreLib/src/System.Private.CoreLib.Shared.projitems

@@ -444,6 +444,7 @@
     <Compile Include="$(MSBuildThisFileDirectory)System\Numerics\Vector3`1.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)System\Numerics\Vector4.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)System\Numerics\Vector4_Intrinsics.cs" />
+    <Compile Include="$(MSBuildThisFileDirectory)System\Numerics\Vector4_1.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)System\Numerics\VectorMath.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)System\Object.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)System\ObjectDisposedException.cs" />