p4raw-id: //depot/perl@14109
arrays before sorting.
A stable sort means that for records that compare equal, the original
-input ordering is preserved. Perl's mergesort is stable, quicksort is not.
+input ordering is preserved. mergesort is stable, quicksort is not.
Stability will matter only if elements that compare equal can be
distinguished in some other way. That means that simple numerical
and lexical sorts do not profit from stability, since equal elements