Remove WeavingAdaptor.couldWeave()

Remove WeavingAdaptor.couldWeave()

WeavingAdaptor.couldWeave() tested two things: whether this specific
class (by its name) should be excluded from weaving, and whether the
class has generated classes associated with it (in which case we avoid
weaving to avoid re-creating those generated classes). However, if the
class has generated classes associated, couldWeave() is not called at
all because of the new wovenWithGeneratedClass() test, so we have
only the name test which is now called directly.

Relates to #279.