Do primop rep-poly checks when instantiating

This patch changes how we perform representation-polymorphism checking
for primops (and other wired-in Ids such as coerce).
When instantiating the primop, we check whether each type variable
is required to instantiated to a concrete type, and if so we create a
new concrete metavariable (a ConcreteTv) instead of a simple MetaTv.
(A little subtlety is the need to apply the substitution obtained from
instantiating to the ConcreteTvOrigins, see
Note [substConcreteTvOrigin] in GHC.Tc.Utils.TcMType.)

This allows us to prevent representation-polymorphism in non-argument
position, as that is required for some of these primops.

We can also remove the logic in tcRemainingValArgs, except for
the part concerning representation-polymorphic unlifted newtypes.
The function has been renamed rejectRepPolyNewtypes; all it does now
is reject unsaturated occurrences of representation-polymorphic newtype
constructors when the representation of its argument isn't a concrete
RuntimeRep (i.e. still a PHASE 1 FixedRuntimeRep check).
The Note [Eta-expanding rep-poly unlifted newtypes] in GHC.Tc.Gen.Head
gives more explanation about a possible path to PHASE 2, which would be
in line with the treatment for primops taken in this patch.

We also update the Core Lint check to handle this new framework. This
means Core Lint now checks representation-polymorphism in continuation
position like needed for catch#.

Fixes #21906

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Metric Increase:
    LargeRecord
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