I know that in many countries, including the US, the UK, and most, perhaps all, of Europe, it is common for houses to be sold while still under construction, so no such legal prohibition exists (or at least is enforced) in any of those countries. I have never heard of any country which has a general law against such a practice, but I cannot be sure for all countri8es in the world.
There are other was to "prevent contractor delays and/or construction malformations and even constructions deformations". Many counties have building codes, which make improper building techniques unlawful. In some countries failure to adhere to proper professional standards in such matters is unlawful, and it is usual for the purchase of an unfinished building to involve a contract, in which performance standards and dates are spelled out. Failure to adhere to such requirements would give the purchaser grounds for a lawsuit for damages.