0.8.0.78.vector-nil-string.3:

0.8.0.78.vector-nil-string.3:
	Fix most of the performance problem
	... transforms for HAIRY-DATA-VECTOR-{REF,SET} on SIMPLE-STRING

Right.  The all-important "compile sbcl" benchmark is now back to about
where it was (57 minutes on my laptop).  There are still correctness
issues to deal with, not least
  (sxhash (make-array 5 :element-type nil))
but this path isn't proving ridiculously expensive.