This patch uses (forall (a::*). a) for the type to
use when recovering from an error in a binding.

Previously (Trac #15276) we had (forall r (a :: TYPE r). a),
which is ill-kinded.

It's quite hard to provoke an error arising from this, because
it only happens in programs that have a type error anyway,
but in a subequent patch I make typeKind fall over if it returns
an ill-scoped kind, and that makes ghci/scripts/T13202 crash
without this fix.