mprintf: fix the integer overflow checks

mprintf: fix the integer overflow checks

When a floating point precision or string width are provided as a
base-10 number, the code could miss to detect integer overflows if the
provided value was exactly 2147483648 or 2147483649 (2147483647 being
the maxium value a signed integer can hold).

The chance that such values would actually ever be used is slim.

This change fixes the detection to also cover those edge cases.

Closes #15699