This speeds up building everywhere and gets rid of the timeout on
slower architectures. Unfortunately those sometimes fail the 124-tai
test because the tolerances are too tight (0.001004s > 0.001000).
Something for upstream?

- Use make quickcheck instead of make check to avoid >1h build
times and failures due to timeouts. This was the default before
3.2 but it changed to make tests more reliable. Here a seed is
already set to get deterministic execution.