Method add

benchmark/data.js:6–8

(n2)

		this.bits = arg instanceof BitSet ? arg.bits.slice() : [];
	}
	add(n2) {
		this.bits[n2 >> 5] |= 1 << (n2 & 31);
	}
	has(n2) {
		return !!(this.bits[n2 >> 5] & (1 << (n2 & 31)));
	}