Performance enhancement to Bytecode deserialization

There is a bad bottleneck in Jackson deserialization of Bytecode. It doesn't become extremely apparent until higher levels of load are reached and I think is even more evident after the latest bump in Jackson version where a bug fix in Jackson itself changed the way in which deserialization caching for collections was handled. Bytecode deserialization was relying on the standard Jackson collection deserializers and it costs quite considerably in terms of synchronized access to the deserializer cache and to the reflection calls required to sort out types.