Simon Peyton Jones authored Apr 22, 2022 and Marge Bot committed Apr 22, 2022

Second fix to #21391.  It turned out that we missed calling
bringFloatedDictsIntoScope when specialising imports, which
led to the same bug as before.

I refactored to move that call to a single place, in specCalls,
so we can't forget it.

This meant making `FloatedDictBinds` into its own type, pairing
the dictionary bindings themselves with the set of their binders.
Nicer this way.