Tests: optimized fields

mysql-test/suite/versioning/r/optimized_fields.result

@@ -58,6 +58,12 @@ select a from t where b=NULL query for system_time as of timestamp now(6);
 a
 Warnings:
 Warning	4075	Attempt to read unversioned field `b` in historical query
+select a from t where b is NULL query for system_time as of timestamp now(6);
+a
+1
+3
+Warnings:
+Warning	4075	Attempt to read unversioned field `b` in historical query
 select count(*), b from t group by b having b=NULL query for system_time as of timestamp now(6);
 count(*)	b
 Warnings:

mysql-test/suite/versioning/t/optimized_fields.test

@@ -16,6 +16,7 @@ select * from t group by a having a=2 query for system_time as of timestamp now(
 select * from t group by b having b=2 query for system_time as of timestamp now(6);
 select a from t where b=2 query for system_time as of timestamp now(6);
 select a from t where b=NULL query for system_time as of timestamp now(6);
+select a from t where b is NULL query for system_time as of timestamp now(6);
 select count(*), b from t group by b having b=NULL query for system_time as of timestamp now(6);
 select a, b from t;