Description:
------------
This has been originally reported by @danack in bug #55416, which
is related, but not a duplicate.

When an exception is thrown inside a user-defined SQL function, a
spurious warning is additionally shown when a query using this
function is executed, even though the exception is caught.

For reference: <https://3v4l.org/I4TpT>.

Test script:
---------------
<?php
function my_udf_md5($string) {
    throw new \Exception("test exception\n");
}

$db = new SQLite3(':memory:');
$db->createFunction('my_udf_md5', 'my_udf_md5');

try {
    $result = $db->querySingle('SELECT my_udf_md5("test")');
    var_dump($result);
}
catch(\Exception $e) {
    echo "Exception: ".$e->getMessage();
}

Expected result:
----------------
Exception: test exception

Actual result:
--------------
Warning: SQLite3::querySingle(): Unable to execute statement:  in %s on line 10
Exception: test exception