CAS-14719: avoid small ragged trailing block in cube minor cycle partitioning
numblockchans derived blksize from nproc and then took nblk=nchan/blksize,
truncating the division; the remainder was re-appended as an extra, much
smaller trailing block. nblk was routinely nproc+1 and the orphan block
could hold only a few channels. The deconvolver derives its mask-smoothing
beam from the block's own beam subset, where getCommonBeam returns
trivially for a single-beam set but enters ill-conditioned arithmetic for
a few very similar channels. Decide the block count first, rounding up so
no block exceeds optchan, then split the channels evenly.
Configuration changes
Some of the jobs or stages referenced by this result no longer exist.
