benchmark should use monotonic time

[codefromthecrypt]

I think this doesn't really need the discussion first, but just in case:

now() in benchmarks compiles to wasm that uses the real time clock, not the monotonic one.

libsodium/test/default/cmptest.h

Line 119 in 6d56607

static unsigned long long now(void)

I think it should be something like clock_gettime(CLOCK_MONOTONIC, &ts) instead, to ensure better accuracy.

[jedisct1]

Done, thanks! But fo WASI, it doesn't make a difference.

[codefromthecrypt]

cheers yeah it was more the old telemetry person inside me than something that would have changed anything :D