Ditching java.beans.Introspector for instance member discovery.

Beans introspector does not consider public interfaces of restricted
classes. This causes it to not expose i.e.
sun.nio.fs.UnixFileAttributeViews$Basic methods, even though its superclass
sun.nio.fs.AbstractBasicFileAttributeView implements the public
java.nio.file.BasicFileAttributeView interface. However, since both
sun.nio.fs.* classes reside in restricted packages, beans Introspector will
completely skip them. On the other hand, Dynalink's AccessibleMemberLookup
correctly finds and exposes the methods declared on the public interface.

We used to primarily rely on beans Introspector and augment the data it
returned with data from AccessibleMemberLookup. Now we no longer use the
java.beans.* package at all, but instead rely solely on
AccessibleMemberLookup.