Support TLS PRF

[qmuntal]

This PR is the CNG counterpart for golang-fips/openssl#103, golang-fips/openssl#109, and golang-fips/openssl#110.

Description taken from those PRs:

Go 1.21 implements TLS extended master secret (RFC 7627), which uses a different label ("extended master secret") than the original TLS 1.2 PRF ("master secret"). The use of EMS is now required by FIPS 140-3 IG D.Q., and thus the logic needs to be provided by a FIPS certified module (OpenSSL). This adds a new function openssl.TLS1PRF for that.

In other words, crypto/tls implements an algorithm (here that should be provided by OpenSSL/CNG.

[chsienki]

Nit: might want to move this comment above, it was kind of confusing as its explaining what just happened vs what's about to happen (also possible I'm just being slow today, but it took me a minute to understand)

[dagood]

Hmm. I would probably go further and negate it and split it up so it describes what's happening:

func TLS1PRF(secret, label, seed []byte, keyLen int, h func() hash.Hash) ([]byte, error) {
	// TLS 1.0/1.1 PRF uses MD5SHA1.
	algID := bcrypt.TLS1_1_KDF_ALGORITHM
	var hashID string
	if h != nil {
		// If h is specified, assume the caller wants to use TLS 1.2 PRF.
		// TLS 1.0/1.1 PRF doesn't allow specifying the hash function.
		if hashID = hashToID(h()); hashID == "" {
			return nil, errors.New("cng: unsupported hash function")
		}
		algID = bcrypt.TLS1_2_KDF_ALGORITHM
	}