Add a test case with incorrect JSON.

dbms/tests/queries/0_stateless/00918_json_functions.reference

@@ -19,6 +19,7 @@ Array
 200
 300
 1
+0
 --JSONExtractString--
 hello
 hello

dbms/tests/queries/0_stateless/00918_json_functions.sql

@@ -23,6 +23,7 @@ SELECT JSONExtractInt('{"a": "hello", "b": [-100, 200.0, 300]}', 'b', 1);
 SELECT JSONExtractFloat('{"a": "hello", "b": [-100, 200.0, 300]}', 'b', 2);
 SELECT JSONExtractUInt('{"a": "hello", "b": [-100, 200.0, 300]}', 'b', -1);
 SELECT JSONExtractBool('{"passed": true}', 'passed');
+SELECT JSONExtractBool('"HX-=');
 
 SELECT '--JSONExtractString--';
 SELECT JSONExtractString('{"a": "hello", "b": [-100, 200.0, 300]}', 'a');