The spec never mentions the possibility for the `hash` member of
`RsaHashedKeyAlgorithm` to be a string, it should be a `KeyAlgorithm`
object containing a `name` string member.
Spec: https://w3c.github.io/webcrypto/#dfn-RsaHashedKeyAlgorithm
Add support for AES-KW for key wrapping/unwrapping. Very similar
implementation to other AES modes.
Added generic tests for symmetric import and specific AES-KW ones.
Adds ~400 test passes on WPT. Now we do better than Firefox in
`WebCryptoAPI/wrapKey_unwrapKey`!
This implements the last WebCryptoAPI methods `wrapKey` and `unwrapKey`.
Most of the functionality is already there because they rely on
`encrypt` and `decrypt`. The only test failures are for `AES-GCM` which
is not implemented yet.
