This is generated from
    openssl ecparam -genkey -name prime256v1 \
    -out BoringSSLServerTest-ECDSA-P256.key -noout

-----BEGIN EC PRIVATE KEY-----
MHcCAQEEIAaBlGFkA3e1W1vgXB0XDNQh9b+NMiJWlOvd7G90RqiuoAoGCCqGSM49
AwEHoUQDQgAE69H/lXVKCwj9AO+RmNRvHvc+OAOrcjui8wRxn+uljRgWT3LLORwp
mA5xciM+PGmt6ISPcOOA57ZN8iOw7F2ffw==
-----END EC PRIVATE KEY-----