Extended DefaultAopProxyFactory to create Objenesis based proxies if the
library is on the classpath. This allows classes without a default
constructor being CGLib proxied. We're now falling back to original CGLib
based behavior in case the proxy creation using Objenesis fails.
Objenesis 2.0 is now inlined into spring-core to avoid interfering with
other Objenesis versions on the classpath.
Issue: SPR-10594