[R-Forge #2360] Do list names clobber when list is final value of j={...}, too

[arunsrinivasan]

Submitted by: Matt Dowle; Assigned to: Nobody; R-Forge link

Should be fairly straightforward, with a good performance gain.

Highlighted by Steve L offlist on 7 Nov 2012, and with related fix in 1.8.3.

See test 865.

[MichaelChirico]

IINM this is also covered by #3802

[mattdowle]

Closed by #3802