Description:
------------
I would expect the last member of the array returned by libxml_get_errors() to be equal to libxml_get_last_error(), but the former returns an empty array while the latter returns the expected error object.

Reproduce code:
---------------
<?php

$foo = new XMLWriter();
$foo->openMemory();
$foo->startElement("\xEF\xBF\xBF");
var_dump(libxml_get_last_error());
var_dump(libxml_get_errors());
var_dump(libxml_get_last_error() == end(libxml_get_errors()));

Expected result:
----------------
Warning: XMLWriter::startElement(): Char 0xFFFF out of allowed range in /Users/gsnedders/Desktop/test.php on line 5

Warning: XMLWriter::startElement(): Invalid Element Name in /Users/gsnedders/Desktop/test.php on line 5
object(LibXMLError)#2 (6) {
  ["level"]=>
  int(3)
  ["code"]=>
  int(9)
  ["column"]=>
  int(0)
  ["message"]=>
  string(33) "Char 0xFFFF out of allowed range
"
  ["file"]=>
  string(0) ""
  ["line"]=>
  int(0)
}
array(1) {
  [0]=>
  object(LibXMLError)#2 (6) {
    ["level"]=>
    int(3)
    ["code"]=>
    int(9)
    ["column"]=>
    int(0)
    ["message"]=>
    string(33) "Char 0xFFFF out of allowed range
"
    ["file"]=>
    string(0) ""
    ["line"]=>
    int(0)
  }
}
bool(true)

Actual result:
--------------
Warning: XMLWriter::startElement(): Char 0xFFFF out of allowed range in /Users/gsnedders/Desktop/test.php on line 5

Warning: XMLWriter::startElement(): Invalid Element Name in /Users/gsnedders/Desktop/test.php on line 5
object(LibXMLError)#2 (6) {
  ["level"]=>
  int(3)
  ["code"]=>
  int(9)
  ["column"]=>
  int(0)
  ["message"]=>
  string(33) "Char 0xFFFF out of allowed range
"
  ["file"]=>
  string(0) ""
  ["line"]=>
  int(0)
}
array(0) {
}
bool(false)