Function general_repeat 

fn general_repeat<O: OffsetSizeTrait>(
    array: &ArrayRef,
    count_array: &UInt64Array,
) -> Result<ArrayRef>

For each element of array[i] repeat count_array[i] times.

Assumption for the input: 1. count[i] >= 0 2. array.len() == count_array.len()

For example,

array_repeat(
    [1, 2, 3], [2, 0, 1] => [[1, 1], [], [3]]
)