Performance improvement on segment comparison

[alanmcruickshank]

Very very small change, but has a sizable performance impact on segment comparisons, which is important for LT02 performance. This halved the bottleneck speed of the linting step in my large test file. There is almost certainly more work to be done here, but thought I should get this merged first.

[coveralls]

coverage: 100.0%. remained the same when pulling 110bc81 on ac/reflow_perf2 into 6683bb4 on main.

[github-actions]

Coverage Results ✅

Name    Stmts   Miss  Cover   Missing
-------------------------------------
TOTAL   16675      0   100%

219 files skipped due to complete coverage.

[pwildenhain]

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