SI-8894 dealias when looking at tuple components

Classic bait-and-switch: `isTupleType` dealiases, but `typeArgs` does not.
When deciding with `isTupleType`, process using `tupleComponents`.
Similar for other combos. We should really enforce this using extractors,
and only decouple when performance is actually impacted.
Merge pull request #4038 from adriaanm/t8894

SI-8894 dealias when looking at tuple components