Test diff_realroot1 failed during some CI run

[vneiger]

Test diff_realroot1 failed during some CI job (see link below). In many other CI runs these last few days this did not appear. Any possible explanation like randomization and small (but nonzero) probability of failure? Or is there a possible bug that we should chase?

See https://github.com/vneiger/flint/actions/runs/19030225200/job/54342150611#step:13:180

[vneiger]

In a handful of other CI runs, msolve's make check was hanging indefinitely, and this same diff_realroot1 seems to be the cause. See flintlib/flint#2466

[wegank]

Is this the same issue as #230?