Currently we mostly use `toThrow()`, which seems intended for things that throw non-Errors (something that we "forbid" with ESLint).
Hence `toThrowError()` seems more appropriate, and it also simplifies things slightly; see https://jasmine.github.io/api/edge/matchers.html#toThrowError
Since there are no script engine with XFA, the FormCalc parser is not used irl.
The bug @nmtigor noticed was hidden by another one (the wrong check on `match`).