selftests: bpf: crypto: add benchmark for crypto functions

Some simple benchmarks are added to understand the baseline of
performance.

Signed-off-by: Vadim Fedorenko <vadfed@meta.com>
Link: https://lore.kernel.org/r/20240422225024.2847039-5-vadfed@meta.com
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>