EVP API ECDHE speed tool support

[torben-hansen]

Description of changes:

Capture fips vs non-fips performance differences when using EVP API level to do ECDHE.

Call-outs:

non-fips:

$ ./tool/bssl speed -filter "ECDH"                                                                                                        
Did 9250 ECDH P-224 operations in 1001966us (9231.9 ops/sec)
Did 17000 ECDH P-256 operations in 1007707us (16870.0 ops/sec)
Did 4213 ECDH P-384 operations in 1084221us (3885.7 ops/sec)
Did 3003 ECDH P-521 operations in 1098185us (2734.5 ops/sec)
Did 2519 ECDH secp256k1 operations in 1081613us (2328.9 ops/sec)
Did 9250 EVP ECDH P-224 operations in 1002814us (9224.0 ops/sec)
Did 17000 EVP ECDH P-256 operations in 1020140us (16664.4 ops/sec)
Did 3890 EVP ECDH P-384 operations in 1004690us (3871.8 ops/sec)
Did 2730 EVP ECDH P-521 operations in 1000664us (2728.2 ops/sec)
Did 2552 EVP ECDH secp256k1 operations in 1097794us (2324.7 ops/sec)
Did 30000 EVP ECDH X25519 operations in 1011202us (29667.7 ops/sec)

fips:

Notice the drop in the second part of the output.

$ ./tool/bssl speed -filter "ECDH"
Did 10175 ECDH P-224 operations in 1096756us (9277.4 ops/sec)
Did 17000 ECDH P-256 operations in 1006072us (16897.4 ops/sec)
Did 4125 ECDH P-384 operations in 1067952us (3862.5 ops/sec)
Did 2750 ECDH P-521 operations in 1001442us (2746.0 ops/sec)
Did 2618 ECDH secp256k1 operations in 1094624us (2391.7 ops/sec)
Did 3850 EVP ECDH P-224 operations in 1099314us (3502.2 ops/sec)
Did 6800 EVP ECDH P-256 operations in 1002298us (6784.4 ops/sec)
Did 1560 EVP ECDH P-384 operations in 1000189us (1559.7 ops/sec)
Did 1089 EVP ECDH P-521 operations in 1083282us (1005.3 ops/sec)
Did 1023 EVP ECDH secp256k1 operations in 1094584us (934.6 ops/sec)
Did 30000 EVP ECDH X25519 operations in 1012383us (29633.1 ops/sec)

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