* tests/bench-slope.c (bench_print_result_nsec_per_iteration): New.
(bench_print_header_nsec_per_iteration): New.
(kdf_bench_one, kdf_bench): Use new print helper functions.
[USE_ECC]: New ECC benchmarks.
(ecc_bench): New.
(print_help): Add 'ecc' option.
(main): Add ECC benchmarks.