typefindfunctions: Consider the number of atoms found in a row for suggesting a probability
If there are 2 or more known atoms in a row, it's likely that this is actually MOV/MP4 even if we don't find any other known atoms. If 5 or more are found then this is most certainly MOV/MP4 and we can return.
Fixes typefinding of various MOV files that have no ftyp
atom but
otherwise a valid file structure followed by some garbage.