Enforce matching of cipher suite with previous PSK in 0-RTT

[grittygrease]

The PSK cipher suite in early data must match the previously established symmetric cipher.

From the latest spec (12):

6.3.2.5. Early Data Indication The client specifies the cryptographic configuration for the 0-RTT data using the “configuration_id”, “cipher_suite”, and “extensions” values. For configurations received in-band (in a previous TLS connection) the client MUST: Send the same cryptographic determining parameters (Section Section 6.3.2.5.1) with the previous connection. If a 0-RTT handshake is being used with a PSK that was negotiated via a non-PSK handshake, then the client MUST use the same symmetric cipher parameters as were negotiated on that handshake but with a PSK cipher suite.