[ASTERIXDB-2689][FUN] Make numeric functions return NULL on invalid arguments

- user model changes: no
- storage format changes: no
- interface changes: no

Details:
Make numeric functions return NULL on invalid arguments.

Change-Id: Id26229064058c3ecbaa54ece3001d3b8980f8d8b
Reviewed-on: https://asterix-gerrit.ics.uci.edu/c/asterixdb/+/4583
Contrib: Jenkins <jenkins@fulliautomatix.ics.uci.edu>
Tested-by: Jenkins <jenkins@fulliautomatix.ics.uci.edu>
Integration-Tests: Jenkins <jenkins@fulliautomatix.ics.uci.edu>
Reviewed-by: Ali Alsuliman <ali.al.solaiman@gmail.com>
Reviewed-by: Dmitry Lychagin <dmitry.lychagin@couchbase.com>
diff --git a/hyracks-fullstack/NOTICE b/hyracks-fullstack/NOTICE
index 77f31ad..95fe98a 100644
--- a/hyracks-fullstack/NOTICE
+++ b/hyracks-fullstack/NOTICE
@@ -1,5 +1,5 @@
 Apache Hyracks and Algebricks
-Copyright 2015-2019 The Apache Software Foundation
+Copyright 2015-2020 The Apache Software Foundation
 
 This product includes software developed at
 The Apache Software Foundation (http://www.apache.org/).