Sort integers by the number of 1 bits

#[test]
fn t1() {
    let start = std::time::Instant::now();
    let val = Solution::sort_by_bits(vec![0, 1, 2, 3, 4, 5, 6, 7, 8]);
    let expected = vec![0, 1, 2, 4, 8, 3, 5, 6, 7];
    log_result!(val == expected, "t1", start, &expected, &val);
    assert_eq!(val, expected);
}

#[test]
fn t2() {
    let start = std::time::Instant::now();
    let val = Solution::sort_by_bits(vec![1024, 512, 256, 128, 64, 32, 16, 8, 4, 2, 1]);
    let expected = vec![1, 2, 4, 8, 16, 32, 64, 128, 256, 512, 1024];
    log_result!(val == expected, "t2", start, &expected, &val);
    assert_eq!(val, expected);
}

#[test]
fn t3() {
    let start = std::time::Instant::now();
    let val = Solution::sort_by_bits(vec![7, 6, 5, 4, 3, 2, 1, 0]);
    let expected = vec![0, 1, 2, 4, 3, 5, 6, 7];
    log_result!(val == expected, "t3", start, &expected, &val);
    assert_eq!(val, expected);
}

#[test]
fn t4() {
    let start = std::time::Instant::now();
    let val = Solution::sort_by_bits(vec![3]);
    let expected = vec![3];
    log_result!(val == expected, "t4", start, &expected, &val);
    assert_eq!(val, expected);
}

#[test]
fn t5() {
    let start = std::time::Instant::now();
    let val = Solution::sort_by_bits(vec![10000, 10000]);
    let expected = vec![10000, 10000];
    log_result!(val == expected, "t5", start, &expected, &val);
    assert_eq!(val, expected);
}