All these tests are meant to run with OPcache available, and some will even fail inevitably without it, so we add OPcache as SKIPIF requirement.
New modulus range inference implementation has been verified using https://gist.github.com/nikic/67947ff92cf0e1f7e931f2f0d4cf817f. The computed bounds are not tight, but it seems to be very hard to compute tight bounds on modulus operations.