Description:
------------
XML_OPTION_SKIP_WHITE should skip elements if the entire element is whitespace.  Unfortunately it looks like expat calls the character handler on individual xml entities within a string so any whitespace between xml entities is ignored.

Looks like the hhvm guys noticed and "fixed this"

Test script:
---------------
@ https://3v4l.org/4TD9v also

<?php

function handleCharacterData($parser, $data)
{
    echo __FUNCTION__ . " - " . $data . "\n";
}

function handleElementStart($parser, $name, $attributes)
{
    echo __FUNCTION__ . " - " . $name . "\n";
}

function handleElementEnd($parser, $name)
{
    echo __FUNCTION__ . " - " . $name . "\n";
}

function parseAndOutput($s)
{
    $p = xml_parser_create();
    xml_parser_set_option($p, XML_OPTION_SKIP_WHITE, 1);
    xml_set_character_data_handler($p, 'handleCharacterData');
    xml_set_element_handler($p, 'handleElementStart', 'handleElementEnd');

    xml_parse_into_struct($p, $s, $values);
    echo $values[0]['value'] . "\n\n";
}

$s = "<a>b\nc</a>";
parseAndOutput($s);

$s = "<a>&lt;b&gt;\n&lt;c&gt;</a>";
parseAndOutput($s);

Expected result:
----------------
handleElementStart - A
handleCharacterData - b
c
handleElementEnd - A
b
c

handleElementStart - A
handleCharacterData - <b>
<c>
handleElementEnd - A
<b>
<c>


Actual result:
--------------
handleElementStart - A
handleCharacterData - b
c
handleElementEnd - A
b
c

handleElementStart - A
handleCharacterData - <
handleCharacterData - b
handleCharacterData - >
handleCharacterData - 

handleCharacterData - <
handleCharacterData - c
handleCharacterData - >
handleElementEnd - A
<b><c>