Demand: Better representation (#19050)

In #19050, we identified several ways in which we could make more illegal
states irrepresentable. This patch introduces a few representation changes
around `Demand` and `Card` with a better and earlier-failing API exported
through pattern synonyms. Specifically,

1. The old enum definition of `Card` led to severely bloated code of operations
   on it. I switched to a bit vector representation; much nicer overall IMO.
   See Note [Bit vector representation for Card].

Most of the gripes with the old representation were related to where which kind
of `Card` was allowed and the fact that it doesn't make sense for an absent or
bottoming demand to carry a `SubDemand` that describes an evaluation context
that is never realised.

2. So I refactored the `Demand` representation so that it has two new data
   constructors for `AbsDmd` and `BotDmd`. The old `(:*)` data constructor
   becomes a pattern synonym which expands absent demands as needed, so that
   it still forms a complete match and a versatile builder. The new `Demand`
   data constructor now carries a `CardNonAbs` and only occurs in a very limited
   number of internal call sites.
3. Wherever a full-blown `Card` might end up in a `CardNonAbs` field (like that
   of `D` or `Call`), I assert the consistency. When the smart builder of `(:*)`
   is called with an absent `Card`, I assert that the `SubDemand` is the same
   that we would expand to in the matcher.
4. `Poly` now takes a `CardNonOnce` and encodes the previously noticed invariant
   that we never produce `Poly C_11` or `Poly C_01`. I made sure that we never
   construct a `Poly` with `C_11` or `C_01`.

Fixes #19050.

We lose a tiny bit of anal perf overall, probably because the new `Demand`
definition can't be unboxed. The biggest loser is WWRec, where allocations go
from 16MB to 26MB in DmdAnal, making up for a total increase of (merely) 1.6%.
It's all within acceptance thresholds.
There are even two ghc/alloc metric decreases. T11545 decreases by *67%*!

Metric Decrease:
    T11545
    T18304