RFR 7065380 : Allow Collections.sort to sort Collections.singletonList() result

[Mike Duigou]

Hello all;

Currently Collections.sort() refuses to sort the lists which result from calling Collections.singletonList(). This makes some sense because the singleton lists are immutable but they are also alway sorted.

This patch allows Collections.sort() to be used with empty and singleton lists of all types. A short circuit return is provided for lists of length 0 and 1 as they are already sorted.

WEBREV @ http://cr.openjdk.java.net/~mduigou/7065380/0/webrev/

For the unit test ignore the diffs and view the "New" file--webrev doesn't understand "hg copy".

Thanks,

Mike