Fix build failure due to conflict between concurrent PRs

New usage of Interop.libc.close was added while it was
simultaneously being removed in another PR, which defeated
catching it via CI PR validation.

Author: nguerrera

src/Common/src/System/Net/SocketProtocolSupportPal.Unix.cs

@@ -81,7 +81,7 @@ private static bool IsProtocolSupported(AddressFamily af)
             {
                 if (socket != -1)
                 {
-                    Interop.libc.close(socket);
+                    Interop.Sys.Close(socket);
                 }
             }
         }

src/System.Net.NameResolution/src/System.Net.NameResolution.csproj

@@ -155,8 +155,8 @@
     <Compile Include="$(CommonPath)\Interop\Unix\Interop.Libraries.cs">
       <Link>Interop\Unix\Interop.Libraries.cs</Link>
     </Compile>
-    <Compile Include="$(CommonPath)\Interop\Unix\libc\Interop.close.cs">
-      <Link>Interop\Unix\libc\Interop.close.cs</Link>
+    <Compile Include="$(CommonPath)\Interop\Unix\System.Native\Interop.Close.cs">
+      <Link>Interop\Unix\System.Native\Interop.Close.cs</Link>
     </Compile>
     <Compile Include="$(CommonPath)\Interop\Unix\libc\Interop.freeaddrinfo.cs">
       <Link>Interop\Unix\libc\Interop.freeaddrinfo.cs</Link>

src/System.Net.NameResolution/tests/PalTests/System.Net.NameResolution.Pal.Tests.msbuild

@@ -133,8 +133,8 @@
     <Compile Include="$(CommonPath)\Interop\Unix\Interop.Libraries.cs">
       <Link>Interop\Unix\Interop.Libraries.cs</Link>
     </Compile>
-    <Compile Include="$(CommonPath)\Interop\Unix\libc\Interop.close.cs">
-      <Link>Interop\Unix\libc\Interop.close.cs</Link>
+    <Compile Include="$(CommonPath)\Interop\Unix\System.Native\Interop.Close.cs">
+      <Link>Interop\Unix\System.Native\Interop.Close.cs</Link>
     </Compile>
     <Compile Include="$(CommonPath)\Interop\Unix\libc\Interop.freeaddrinfo.cs">
       <Link>Interop\Unix\libc\Interop.freeaddrinfo.cs</Link>