revert system.net stubs

Author: 5idg5

csharp/ql/test/resources/stubs/System.Net.cs

@@ -50,21 +50,6 @@ public class StringContent
         public StringContent(string s) { }
     }
 
-    public class HttpResponseMessage : IDisposable
-    {
-        public HttpResponseMessage() { }
-        public HttpResponseMessage(HttpStatusCode statusCode) { }
-
-
-        public Version Version { get; set; }
-        public HttpContent Content { get; set; }
-        public HttpStatusCode StatusCode { get; set; }
-        public HttpResponseHeaders Headers { get; }
-        public HttpRequestMessage RequestMessage { get; set; }
-        public bool IsSuccessStatusCode { get; }
-    }
-
-
 }
 
 namespace System.Net.Mail