Delete file moved to shared CoreLib.

Author: filipnavara

src/System.Private.CoreLib/System.Private.CoreLib.csproj

@@ -178,7 +178,6 @@
     <Compile Include="$(BclSourcesRoot)\System\mda.cs" />
     <Compile Include="$(BclSourcesRoot)\System\MissingMemberException.CoreCLR.cs" />
     <Compile Include="$(BclSourcesRoot)\System\MulticastDelegate.cs" />
-    <Compile Include="$(BclSourcesRoot)\System\Numerics\Hashing\HashHelpers.cs" />
     <Compile Include="$(BclSourcesRoot)\System\Object.CoreCLR.cs" />
     <Compile Include="$(BclSourcesRoot)\System\OleAutBinder.cs" Condition="'$(FeatureClassicCominterop)' == 'true'" />
     <Compile Include="$(BclSourcesRoot)\System\Reflection\Assembly.CoreCLR.cs" />