perf(utils): further optimise subset check.

[yuroitaki]

As tlsnotary/tlsn#664 starts using is_subset checks, I implemented a small optimisation — immediately return false if the subset candidate's left and right boundaries are not within/same as the other rangeset.

[themighty1]

lgtm

[sinui0]

Lgtm, but performance optimizations would ideally come with a benchmark proving they are faster

[yuroitaki]

Lgtm, but performance optimizations would ideally come with a benchmark proving they are faster

do you mean adding a bench.rs in the code, or attaching the result of manual benching in this PR?

[yuroitaki]

Benchmark results after optimisation in my m2 max macbook below:

TLDR:
(1) No impact in the worst case for subset check of range against rangeset.
(2) Significant improvement in the worst case for subset check between rangesets.

(1) most likely because each of the iteration saved by the short-circuit optimisation only does very little work, i.e. continue, which doesn't amount to any noticeable performance improvement.