IntervalTests runs every op over 10,000 seeded intervals x 16 points with no tolerance, and
kills each op's one-ulp-shrunk lo and hi; exp's widening is an equivalent mutant on this CPU,
and smoothstep's is killed by a constructed non-monotone step. NoiseBoundTests encloses snoise
and fbm over 2,000 balls x 64 points and the bounded domain warp, pins SNOISE_LIPSCHITZ against
1e5 points and the ascent from MeasureLipschitz's witness, prints tightness, and prints the
march saving. The saving is 0.93x, not 2x: that test skips with the fork named.
MeasureLipschitz and MeasureMonotonicity are explicit, slow tests.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
