[ji] make inspect on Java proxies work #5219
the motivation here is #5182 ... have seen "useless" hashy-inspect on Java proxied types too many times.
the approach here is the following: proxies use a call-site to determine whether
there's likely a "cleaner" way -> having
in terms of compatibility there's some "breaking" change related to
e.g. previously a instance_method(:toString) would only exists on java.lang.Object - custom impls in more concrete classes would not show up. which is fine to save space due Java's dispatch rules but the proxy class hierarachy doesn't match reality which we'll need for Java inspect -> toString
need a base to_s impl on java.lang.Object - calling toString() refactored the Java object proxy class tracking in JavaSupport