Previously, the state hack would be implemented in mkLocalId, by looking
at the type, and setting the OneShot flag accordingly.

This patch changes this so that the OneShot flag faithfully represents
what our various analyses found out, and the State Hack is implemented
by adjusting the accessors, in particular isOneShotBndr and
idStateHackOneShotInfo. This makes it easier to understand what's going
on in the analyses, and de-clutters core dumps and interface files.

I don’t expect any change in behaviour, at least not in non-fringe
cases.