qmlsc: Support storing JS arrays in JS variables

import QtQuick

Window {
    width: 640
    height: 480
    visible: true

    property list<int> numbers

    function foo(): int {
        let jsArray = [1, 2, 3]
        numbers = jsArray
        return jsArray[0]
    }
}

    property list<int> numbers
    function foo(): int {
        numbers = [1, 2, 3]
        let jsArray = numbers
        return jsArray[0]
    }