Rather than instantiating a UTF8 encoding everywhere when we want to supress the BOM, use a single Util.UTF8NoBomEncoding.

This class is thread-safe (as evidenced by the provision of the system-wide Encoding.UTF8 which does not suppress BOM on output).

OpenSim/Region/ScriptEngine/Shared/Instance/ScriptInstance.cs

@@ -952,7 +952,7 @@ namespace OpenSim.Region.ScriptEngine.Shared.Instance
                 try
                 {
                     FileStream fs = File.Create(Path.Combine(Path.GetDirectoryName(assembly), ItemID.ToString() + ".state"));
-                    Byte[] buf = (new UTF8Encoding()).GetBytes(xml);
+                    Byte[] buf = Util.UTF8NoBomEncoding.GetBytes(xml);
                     fs.Write(buf, 0, buf.Length);
                     fs.Close();
                 }