test both arguments of getConnection

Co-authored-by: Tony Torralba <atorralba@users.noreply.github.com>

java/ql/test/query-tests/security/CWE-798/semmle/tests/HardcodedMSSQLCredentials.java

@@ -4,6 +4,7 @@ public class HardcodedMSSQLCredentials {
     public static void main(SQLServerDataSource ds) throws Exception {        
         ds.setUser("Username"); // $ HardcodedCredentialsApiCall      
         ds.setPassword("password"); // $ HardcodedCredentialsApiCall
-        ds.getConnection("Username", "password"); // $ HardcodedCredentialsApiCall
+        ds.getConnection("Username", null); // $ HardcodedCredentialsApiCall
+        ds.getConnection(null, "password"); // $ HardcodedCredentialsApiCall
       }
 }