Integrate BoringSSL test suite (BoGo)

[duesee]

See https://github.com/google/boringssl/blob/master/ssl/test/PORTING.md and https://github.com/rustls/rustls/blob/main/rustls/examples/internal/bogo_shim.rs.

Issues

• Implement alerts
• Detect missing key shares (MissingKeyShare-Server-TLS13)
• Detect duplicate key shares (DuplicateKeyShares-TLS13)
• Server doesn't correctly returns session ID (EmptySessionID-TLS13, Server-ShortSessionID-TLS13, Server-FullSessionID-TLS13)
• Server doesn't correctly handle too long session ID (Server-TooLongSessionID-TLS13)
• Server should accept any record version for compatibility reasons (LooseInitialRecordVersion-TLS13)
• decrypt_handshake should ignore user_canceled warning alert (SendUserCanceledAlerts-TLS13)
  • decrypt_handshake doesn't handle (post-handshake) alerts (SendBogusAlertType, EmptyCertificateList-TLS13)
  • decrypt_handshake must handle bad records/ciphertexts (TLSFatalBadPackets, TLS13-EmptyRecords, TLS13-OnlyPadding, SkipEarlyData-OmitEarlyDataExtension-TLS13, SkipEarlyData-Interleaved-TLS13)
  • decrypt_handshake must handle invalid certificates (GarbageCertificate-Client-TLS13)
• handle key update (TooManyKeyUpdates, KeyUpdate-ToClient, KeyUpdate-ToServer, KeyUpdate-InvalidRequestMode, KeyUpdate-RequestACK)
• finish digest not checked (BadFinished-Client-TLS13, BadFinished-Server-TLS13)
• correctly handle HRR (UnnecessaryHelloRetryRequest-TLS13, SecondHelloRetryRequest-TLS13, HelloRetryRequest)
• check key usage bit (ECDSAKeyUsage-Client-TLS13)

[jallmann]

I'm currently working on this.

[jallmann]

I noticed that a large number of BoGo test cases currently fail because the BoGo runner and the Bertie shim are unable to agree on a cipher suite. The reason is, that Bertie is temporarily unable to do RSA, while the BoGo runner defaults to RSA for the TLS1.3 cipher suites and by default loads a RSA certificate for most test cases.
See:
https://github.com/google/boringssl/blob/ad57528d2c978543106f9b115bd0eb658f3ebdd2/ssl/test/runner/runner.go#L769
https://github.com/google/boringssl/blob/ad57528d2c978543106f9b115bd0eb658f3ebdd2/ssl/test/runner/cipher_suites.go#L56

Bertie needs to support RSA again for this large number of test cases to pass, or at least to reveal their actual failure reasons. I have verified that some test cases advance further and give different failure reasons if I force the BoGo runner to load an ECDSA certificate instead.