Usually avoid the sort in WrappingRange::smallest_range_containing

[scottmcm]

I wasn't planning on touching this again, but I had a shower thought: we've been sorting these for a while because that's better than doing a quadratic check for usable wraparound ranges, but actually we often don't need to.

So long as the obvious min..=max range is small enough, we don't need to bother even looking for a wrapping range!

Now, I don't think this code is particularly hot -- you'd need lots of enums or particularly big ones before it would really matter -- but this does let us short-circuit for even fairly complex enums like mem::alignment.

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• I did not use an LLM to create a change in this PR.

[scottmcm]

@bors try @rust-timer queue

[rust-timer]

Awaiting bors try build completion.

@rustbot label: +S-waiting-on-perf

[rust-bors]

☀️ Try build successful (CI)
Build commit: d0d0b8b (d0d0b8bc325afb707fbc76fb45f437b5d32c6ce4)
Base parent: 88f7399 (88f7399cb4912680976e1c342ea7661b9dc84940)

[rust-timer]

Queued d0d0b8b with parent 88f7399, future comparison URL.
There are currently 10 preceding artifacts in the queue.
It will probably take at least ~10.9 hours until the benchmark run finishes.