Re: Fix some corner cases that cube_in rejects

The following review has been posted through the commitfest application:
make installcheck-world:  tested, passed
Implements feature:       tested, passed
Spec compliant:           tested, passed
Documentation:            not tested

Note for committer :  There are unnecessary files (cube_1.out, cube_2.out & cube_3.out) in contrib directory, that need
tobe removed at code checkin,  other than this concern, I think this patch looks pretty reasonable. Thanks.
 

Regards,
Amul

The new status of this patch is: Ready for Committer