Fix for array lower-bound check for count-down loops.

If the counted loop is composed as

for (int i = hi; i >= lo; i--) {
    .. = array[i];
}

The hoisted lower-bound check should be asserting "lo >= 0".
On the other hand if the counted loop is composed as

for (int i = hi; i > lo; i--) {
    .. = array[i];
}

The hoisted lower-bound check should be asserting "lo + 1 >= 0".
Previously these two checks are reversed.

Bug: 3130818
Change-Id: Ibc5a6daa837880e9986e45bbc29d1a5e548be3ae