Support Nan equals Nan

[loneylee]

In spark UT GlutenDataFrameAggregateSuite

val nan1 = java.lang.Float.intBitsToFloat(0x7f800001)
val nan2 = java.lang.Float.intBitsToFloat(0x7fffffff)
val nan3 = Float.NaN
// gluten count(distinct ) = 3
// spark count(distinct ) = 1

how to fix?

bool equalsOp(A a, B b)
{
    if constexpr (std::is_same_v<A, B>)
    {
        // add begin
        if (isNaN(a) && isNaN(b)) 
        {
            return true;
        }
        // add end
        return a == b;
    }

    /// float vs float
    if constexpr (std::is_floating_point_v<A> && std::is_floating_point_v<B>)
        return a == b;
    
    ...
}