Fix a bug where Collections.unmodifiableMap's entrySet toArray method tries
to wrap extra elements in the array, including the null marking the end of
the elements.

Also, fixed a bug where toArray() went through the array twice and cleaned
up CollectionsTest (generics, sort order).

Patch by: hhchan, jat
Review by: jat


git-svn-id: https://google-web-toolkit.googlecode.com/svn/trunk@7332 8db76d5a-ed1c-0410-87a9-c151d255dfc7