Make Numeric.sum return null when there are no inputs or all null inputs

[chipkent]

Make Numeric.sum return null when there are no inputs or all null inputs. This makes the method consistent with the aggregations.

[rcaudy]

Do we want to handle infinities the way aggBy does?

    private double currentValueWithSum(long totalNormalCount, long totalNanCount, long totalPositiveInfinityCount,
            long totalNegativeInfinityCount, double newSum) {
        if (totalNanCount > 0 || (totalPositiveInfinityCount > 0 && totalNegativeInfinityCount > 0)) {
            return Double.NaN;
        }
        if (totalNegativeInfinityCount > 0) {
            return Double.NEGATIVE_INFINITY;
        }
        if (totalPositiveInfinityCount > 0) {
            return Double.POSITIVE_INFINITY;
        }
        if (totalNormalCount == 0) {
            return QueryConstants.NULL_DOUBLE;
        }
        return (double) newSum;
    }

[chipkent]

Larry and I had a discussion on this before the prior fix. It is unnecessary because of how IEEE754 does things. Look at the unit tests.

[deephaven-internal]

Labels indicate documentation is required. Issues for documentation have been opened:

Community: deephaven/deephaven-docs-community#207