fix(divan): use busy sleep in time scale examples
For these times, using `thread::sleep` makes no sense as, at least on
linux, the scheduler's timer resolution is orders of magnitude larger
than nanoseconds.
Remove `uuid` dependency
`uuid` pulls in a bunch of WASM dependencies, even when Codspeed is pulled in with `default-features = false`. For some projects, that means vetting a lot of extra code.
This PR replaces the `uuid` dependency and uses `getrandom` to generate an UUIDv4-style string. (I'm not sure if anything depends on things being named with UUIDs; if not, this PR would be even simpler.)
chore(divan_compat_examples): switch time_scale benches to busy sleeping
Since the os thread scheduler is orders of magnitude ahead, it makes no
sense to use thread::sleep for such small benchmarks