get_icu_value_internal out-of-bounds read

How it was found

https://bugs.php.net/bug.php?id=72241

Absence of null character terminator causes unexpected zend_string length and leaks heap memory when using several intl functions that commonly receive user input:

• locale_canonicalize
• locale_filter_matches
• locale_lookup
• locale_parse
• locale_get_primary_language

This affected PHP version 5.5, 5.6 and 7.0, patch released today:

http://php.net/ChangeLog-5.php#5.5.36