fix(node/crypto): support promisify on generateKeyPair (#26913)
Calling `promisify(generateKeyPair)` didn't work as expected. It
requires a custom promisify implementation.
This was easy to fix thanks to the excellent debugging investigation in
https://github.com/denoland/deno/issues/26910
Fixes https://github.com/denoland/deno/issues/26910
Co-authored-by: Bartek Iwańczuk <biwanczuk@gmail.com>
