The override function `ensureTerminator` ensures that the terminator `InParallelOp` has a region. However, if the terminator of `scf.forall` is not an `InParallelOp`, calling ensureTerminator causes a crash. Since the InParallelOp builder already guarantees the existence of a region, `ForallOp::ensureTerminator` is redundant and can be safely removed. Fixes #130019.