Problematic unexpand-abbrev behavior: 23.X

[JD Smith]

Consider:

	(define-abbrev global-abbrev-table "foo" "bar" (lambda () (unexpand- 
abbrev)))

unexpand-abbrev in this context has a different behavior from 22.2 to  
23.X.  The latter incorrectly leaves point before the expanded (and  
subsequently unexpanded) text.  At some point, unexpand-abbrev was re- 
implemented in lisp, and its save-excursion seems to cause this.  This  
impacts modes which unexpand abbrevs during the abbrev hook in quoted  
text or comments, where they shouldn't be expanded.

JD