A nonzero polynomial over a characteristic-zero domain has a nonzero value at an integer
point with every coordinate between 0 and its degree. This is the combinatorial
Nullstellensatz MvPolynomial.eq_zero_of_eval_zero_at_prod_finset on the grid {0,...,D}.
A nonzero polynomial with coordinate degrees at most D has a nonzero value on the
integer grid {0,...,D}, in any finite number of variables. Unlike the total-degree version,
the side length does not grow with the number of variables.
A nonzero polynomial of total degree at most A over a characteristic-zero domain has a
nonzero value on the integer grid {0,...,A}.
The integer case of exists_integer_grid_eval_ne_zero_of_totalDegree. The bound is
independent of the number and names of the coordinates.