S11N: Util: Add setter() which returns a method handle via which we can (re)set a field during deserialization.
S11N: Util: Add setter() which returns a method handle via which we can (re)set a field during deserialization.

jvasileff/ceylon.language,ceylon/ceylon.language,unratito/ceylon.language,unratito/ceylon.language,jvasileff/ceylon.language,ceylon/ceylon.language