This table is not used anywhere in the code.

The only reason we did that was to keep the OIDs the same across major
version upgrades, because the old catalog upgrade mechanism relied on
being able to read old catalog version with new binaries. We no longer try
to maintain that property - future upgrades will use pg_upgrade or
something similar that can deal with more drastic catalog changes.

This allows removing the hacks in bootparse.y, toasting.c, and elsewhere,
reducing the chance of merge conflicts in the future.

It was just syntax and catalogs, you couldn't actually do anything useful
with it. Remove it, so that we have less code to maintain, until it's time
to merge this stuff from upstream again when we merge with PostgreSQL 8.4.
It's probably easier to merge this back at that point than maintain this
backported version in the meanwhile. Less effort now, until we reach that
point, and once we get to the point in 8.4 that we merge this in, we'll
have all the preceding patches applied already, so it should merge quite
smoothly.