Description:
------------
I've noticed that PDO exhibits the same erroneous behavior
that has been reported as bug #79084 regarding MySQLi, namely
that PDO::FETCH_BOTH may mess up numeric indexes, if there are
numeric column names.

While this has been reported as bug #44190 long ago, and that
ticket has been closed as not a bug, I think we should reconsider.


Test script:
---------------
<?php
$pdo = new PDO('sqlite::memory:');
$stmt = $pdo->query("SELECT 0 as `2007`, 0 as `2008`, 0 as `2020`");
var_dump($stmt->fetchAll());
?>


Expected result:
----------------
array(1) {
  [0]=>
  array(6) {
    [0]=>
    string(1) "0"
    [2007]=>
    string(1) "0"
    [1]=>
    string(1) "0"
    [2008]=>
    string(1) "0"
    [2]=>
    string(1) "0"
    [2020]=>
    string(1) "0"
  }
}


Actual result:
--------------
array(1) {
  [0]=>
  array(5) {
    [2007]=>
    string(1) "0"
    [2008]=>
    string(1) "0"
    [2009]=>
    string(1) "0"
    [2020]=>
    string(1) "0"
    [2021]=>
    string(1) "0"
  }
}