OrderByDescending sorts incorrectly if a comparer returns int.MinValue

[JonHanna]

int.MinValue is of course traditionally considered less than 0. It is therefore a valid "x is less than y" return value for IComparer<T>.Compare(T x, T y).

But if an implementation returns it when it is correct, then Enumerable.OrderByDescending will treat it indicating that y is greater than x.

Demonstrating test case:

private class ExtremeComparer : IComparer<int>
{
    public int Compare(int x, int y)
    {
        if (x == y)
            return 0;
        if (x < y)
            return int.MinValue;
        return int.MaxValue;
    }
}
[Fact]
public void OrderByExtremeComparer()
{
    var outOfOrder = new[] { 7, 1, 0, 9, 3, 5, 4, 2, 8, 6 };
    Assert.Equal(Enumerable.Range(0, 10), outOfOrder.OrderBy(i => i, new ExtremeComparer()));
    Assert.Equal(Enumerable.Range(0, 10).Reverse(), outOfOrder.OrderByDescending(i => i, new ExtremeComparer()));
}

The second assertion fails, as rather than the expected 9, 8, 7, 6, 5, 4, 3, 2, 1, 0, the result is 3, 5, 1, 4, 9, 2, 0, 8, 7, 6.