Also, when generating RSA keys in JS, generate them with p < q, as per
the spec.
Also, when generating RSA keys using Web Crypto or Node crypto, swap the
generated p and q around, so that will satisfy p < q in most browsers
(but not old Microsoft Edge, 50% of the time) and so that we can use the
generated u coefficient (p^-1 mod q in OpenPGP, q^-1 mod p in RFC3447).
Then, when signing and verifying, swap p and q again, so that the key
hopefully satisfies Safari's requirement that p > q, and so that we can
keep using u again.
