Use fastutil to sort serial numbers

fasutil allows using longs instead of Longs, this avoids
autoboxing/unboxing.

Author: acogoluegnes

pom.xml

@@ -497,6 +497,7 @@
                 <configuration>
                     <java>
                         <excludes>
+                            <exclude>src/main/java/com/rabbitmq/client/amqp/impl/FastUtil*.java</exclude>
                             <exclude>src/test/java/com/rabbitmq/client/amqp/docs/*.java</exclude>
                             <exclude>src/test/java/SanityCheck.java</exclude>
                         </excludes>