[DBTNG + simpletest] queryRange() need update and simpletest test case

Patch update:

1. Remove legacy backward compatible code.
2. Update for better simpletest test cases.

@catch: just take it easy that we are now able to remove these "duplicated" backward compatible code :-D

db_query_range() is now protected with backward compatible function _db_query_process_args():

function db_query_range($query, $args, $from = 0, $count = 0, $options = array()) {
  if (!is_array($args)) {
    $args = func_get_args();
    array_shift($args);
    $count = array_pop($args);
    $from = array_pop($args);
  }
  list($query, $args, $options) = _db_query_process_args($query, $args, $options);

  return Database::getActiveConnection($options['target'])->queryRange($query, $args, $from, $count, $options);
}

Therefore we don't need to run those "tiny and incomplete" backward compatible code within queryRange() again...

On the other hand, db_query_range() is mainly used by pager_query(). By checking CVS HEAD, we can find that dblog.admin.inc line 111 is now using legacy syntax:

  $result = pager_query("SELECT COUNT(wid) AS count, message, variables FROM {watchdog} WHERE type = '%s' GROUP BY message, variables " . tablesort_sql($header), 30, 0, "SELECT COUNT(DISTINCT(message)) FROM {watchdog} WHERE type = '%s'", $type);

When checking admin/reports/pages with apply of this patch, it should still running correctly :-)

For point 3: we need to test unnamed placeholders, because it is supported by PDO and also documented for our db_query_range():

 * @param $args
 *   An array of values to substitute into the query.  If the query uses named
 *   placeholders, this is an associative array in any order.  If the query uses
 *   unnamed placeholders (?), this is an indexed array and the order must match
 *   the order of placeholders in the query string.

Others are simplify based on suggestion :D

P.S. Just a little promotion: may we also give some love to its sister issue?
#322457: [DBTNG + simpletest]: queryTemporary() is buggy and need simpletest test case

Patch reroll via CVS HEAD. No change. Pump as critical so we will not miss it :-)

Patch revamp based on above suggestion.

Merge with progress of #325895: [DBTNG + simpletest] queryTemporary is broken and need simpletest test case and sync their coding style. Other improvement:

1. DatabaseRangeQueryTestCase is now extends from DrupalWebTestCase, so performance boosted.
2. Also check if return target data, besides check if return correct number of rows.
3. Keep db_query_range() comments as existing. According to chx comment the remove of hits for unnamed placeholders should belongs to another issue.

Patch via CVS HEAD and simpletest with MySQL, pass.

Minor documentation update for getInfo()'s description.

Patch reroll via CVS HEAD.