Remove trailing zeros from a string

#[test]
fn t1() {
    let start = std::time::Instant::now();
    let val = Solution::remove_trailing_zeros("51230100".to_string());
    let expected = "512301".to_string();
    log_result!(val == expected, "t1", start, &expected, &val);
    assert_eq!(val, expected);
}

#[test]
fn t2() {
    let start = std::time::Instant::now();
    let val = Solution::remove_trailing_zeros("123".to_string());
    let expected = "123".to_string();
    log_result!(val == expected, "t2", start, &expected, &val);
    assert_eq!(val, expected);
}

#[test]
fn t3() {
    let start = std::time::Instant::now();
    let val = Solution::remove_trailing_zeros("1000".to_string());
    let expected = "1".to_string();
    log_result!(val == expected, "t3", start, &expected, &val);
    assert_eq!(val, expected);
}

#[test]
fn t4() {
    let start = std::time::Instant::now();
    let val = Solution::remove_trailing_zeros("10".to_string());
    let expected = "1".to_string();
    log_result!(val == expected, "t4", start, &expected, &val);
    assert_eq!(val, expected);
}

#[test]
fn t5() {
    let start = std::time::Instant::now();
    let val = Solution::remove_trailing_zeros("100200300".to_string());
    let expected = "1002003".to_string();
    log_result!(val == expected, "t5", start, &expected, &val);
    assert_eq!(val, expected);
}

#[test]
fn t6() {
    let start = std::time::Instant::now();
    let val = Solution::remove_trailing_zeros("9".to_string());
    let expected = "9".to_string();
    log_result!(val == expected, "t6", start, &expected, &val);
    assert_eq!(val, expected);
}