s3/profile: remove the magical clock initialization from the profile code

s3/profile: remove the magical clock initialization from the profile code

there's no point in not profiling times if no monotonic clock is found -
monotonic and realtime clock are equally fast. Just use clock_gettime_mono
instead.
(cherry picked from commit 4e8d6a779c9aa9b9418b4f835d831ad4492c3f6c)