[lworld] C1 support for array covariance for aaload

C1 should support loading of elements in a flattened array, even if the array has been casted to an Object[].

Example:

public class CovLoad {
    static final value class V {
        final int v0 = 0, v1 = 0;
    }

    static Object test(Object arr[], int i) {
        return arr[i]; // << HERE
    }

    static Object[] cast(Object arr) {
        return (Object[])arr;
    }

    public static void main(String args[]) {
        V[] arr = new V[1];
        arr[0] = V.default;
        Object[] oarr = cast(arr);
        System.out.println(test(oarr, 1));
    }
}