Those are not cracks. It is where the concrete was poured and had a chance to set for a while, perhaps while another part of the foundation was being poured. The concrete chute or hose then returned to the area in question, and resumed pouring, allowing the coarser aggregate to show at the joint.
It may also be a cold joint, where concrete was started, then finished later in the day or a different day.
It may also be where the concrete was not vibrated enough in the area to settle in the coarse aggregate. Vibrating concrete helps eliminate air pockets along the form walls. Sometimes air gets trapped, creating what is called "honeycombing"
Any of these conditions although not great, since they are really small, will not create leaks in the basement. Concrete is a big sponge anyway, soaking up moisture, and releasing it to the dryer side, always trying to find equilibrium. The foundation needs a good layer of foundation coat to keep water at bay.