RelOptInfo.all_partrels does not seem to do very much

Hi,

I was just looking at RelOptInfo's partitioning fields and noticed
that all_partrels seems to be set in a couple of places but never
actually referenced.

The field was added in c8434d64c - Allow partitionwise joins in more
cases for PG13.

Maybe it did something during the development of that patch but the
code didn't end up being committed?

Should we get rid of it before it's too late for PG14?

David