Create specially-solved DataToTag class

Closes #20532. This implements CLC proposal 104:
  https://github.com/haskell/core-libraries-committee/issues/104



The design is explained in Note [DataToTag overview]
in GHC.Tc.Instance.Class. This replaces the existing
`dataToTag#` primop.

These metric changes are not "real"; they represent Unique-related
flukes triggering on a different set of jobs than they did previously.
See also #19414.

Metric Decrease:
    T13386
    T8095
Metric Increase:
    T13386
    T8095

Co-authored-by: Simon Peyton Jones <simon.peytonjones@gmail.com>