Code Review Request for 4533691 (add Collections.EMPTY_SORTED_SET)

[Darryl Mocek]

Hello.  Please review this patch to add empty sorted set to the 
Collections class.  Test case provided.

Webrev: http://cr.openjdk.java.net/~mduigou/4533691/1/webrev/
Additional Notes to Reviewers:
The sets resulting from tailSet() headSet() and subSet() normally 
include the range which was used to create them. Using these methods 
with emptySortedSet() does not currently set a range on the resulting sets.

Thanks,
Darryl