Fix Module#define_method
Fix Module#define_method

When defining a method through a proc which gets created out of a method
which is defined in a C-ext, `meth.ruby_method.executable` is a instance of
Rubinius::NativeCode and not Rubinius::CompiledCode which does not
respond to #scope.

This is used for example in pg gem:
https://github.com/ged/ruby-pg/blob/bb4693e811f9348f202835e701e6509d15685b0a/lib/pg/connection.rb#L187

jsyeo/rubinius,jsyeo/rubinius,kachick/rubinius,jsyeo/rubinius,jsyeo/rubinius,kachick/rubinius,kachick/rubinius,jsyeo/rubinius,kachick/rubinius,kachick/rubinius,kachick/rubinius,kachick/rubinius,jsyeo/rubinius,jsyeo/rubinius,kachick/rubinius