Make AdvancedEnhancer jarjar'able

Patching in an upstream change from CGLIB:
https://github.com/cglib/cglib/commit/e90a0c98faaf4ae00d400360ecd67943778468cb
https://github.com/cglib/cglib/commit/6adc08739a2042832f8a8dfa615d6ba87f838525