Which would more likely break when dropped: A full bottle or an empty one?

I would bet on the full bottle. Whether the liquid absorbs the shock or generates destructive shock waves won't come into play until after the initial contact between the outside of the glass and the floor. At that moment glass will deform, and it will break if the deformation exceeds structural limits. Deformation is caused by stress, and stress on impact will be proportionate to the mass of the bottle. Full bottle is heavier.

A liquid filled bottle is more likely to break.

Actually, they will both have the same velocity, since all objects fall at the same rate until they reach terminal velocity. A liquid filled bottle would have a higher terminal velocity but I'm guessing you won't be dropping them from high enough for that to matter.

However, the liquid inside the bottle will produce shock waves and cavitation bubbles that will cause the bottle to break.

First of all sounds like a super fun experiment! An empty bottle would be more likely to break for the reasons that you stated

no one can give you a valid answer you don't state the material of the bottle it can be plastic so i would say none of them.

full bottle because it gets weiged down more,.