b844505ec7
binary_arith! applied an unconditional is_zero() guard, so x - 0n and x * 0n (and wrapped-object variants) incorrectly threw RangeError. Only DIV/MOD legitimately reject BigInt zero divisors; SUB/MUL must compute normally. test262 language/expressions/subtraction: 29/6 -> 30/5 (bigint-arithmetic now passes).