Make assert condition more generic.

Author: Lakshmi Priya Sekar

src/System.Net.Security/tests/FunctionalTests/SslStreamNetworkStreamTest.cs

@@ -106,7 +106,7 @@ public async Task SslStream_NetworkStream_Renegotiation_Succeeds()
 
                 // Do another Read, to get the HTTP response from the server, after successful renegotiation.
                 bytesRead = await ssl.ReadAsync(message, 0, message.Length);
-                Assert.Equal(84, bytesRead);
+                Assert.True(bytesRead > 0);
                 Assert.Contains("HTTP/1.1 200 OK", Encoding.UTF8.GetString(message));
             }
         }