Binary Compatibility: vtable entries for final methods

[Andrew Haley]

"Changing a class that was declared final to no longer be declared
final does not break [binary compatibility.]"

"Removing the final modifier from a method does not break [binary
compatibility.]"

So, our practice of making direct calls to final methods and not
generating vtable entries for them must cease.  I'm minded to make an
exception for java.lang.Object, because we'd otherwise add a bunch of
vtable entries to every single class for no good reason.

Andrew.