swift234

SIL: Fixes for abstraction patterns containing interface types

When lowering the original unsubstituted type to check for parameters
and results being passed indirectly, be careful to map it to archetypes,
since the abstraction pattern's generic signature might not equal
M.Types.getCurGenericContext().

Also, don't use '==' to compare canonical interface types.

NFC for now, since this code is largely not exercised.