Sync with upstream

[SimenB]

Hiya! 👋

Upstream amongst other things has tsdjs@5376484 which I need now (a newer TS compiler) in Jest.

(specifically I need 4.2+ while the bundled version here is 3.9)

/cc @smartclash @SaurabhAgarwala

[SimenB]

When ("if" I guess, but hope not 😅) you get to this, rebasing tsdjs#75 would be nice as well so it can land and we wouldn't need this fork at all 🙂