[CBAS] Conditional functions for Unknowns are not implemented in SQL++

Build : 647

Conditional functions for unknowns are not implemented in SQL+, but they are supported in N1QL. These should be either documented, or fixed in SQL+.

Following are the functions not implemented in SQL++:
IFNAN@2, NANIF@2, POSINFIF@2, IFINF@2, IFMISSINGORNULL@2, MISSINGIF@2

SELECT feature_name, IFNAN(story_point[2],story_point[1]) as point FROM default_shadow ORDER BY feature_name;
SELECT feature_name, NANIF(story_points[0],story_point[0]) FROM default_shadow ORDER BY feature_name;
SELECT feature_name, POSINFIF(story_point[2],story_point[1]) as point FROM default_shadow ORDER BY feature_name;
SELECT feature_name, IFINF(story_point[2],story_point[1]) as point FROM default_shadow ORDER BY feature_name;
SELECT feature_name, IFMISSINGORNULL(coverage_tests.P0,coverage_tests.P4) as C FROM default_shadow ORDER BY feature_name;
SELECT feature_name, MISSINGIF(coverage_tests.P0,0) as point FROM default_shadow ORDER BY feature_name;