Backport 3ec5919: Update error message for libxml 2.13

External entity loading got its error level decreased in upstream,
which means they now map to E_NOTICE. Also the error message format has
changed.

Author: ndossche

ext/libxml/tests/bug61367-read_2.phpt

@@ -56,6 +56,6 @@ bool(true)
 int(4)
 bool(true)
 
-Warning: DOMDocument::loadXML(): %Sfailed to load external entity "file:///%s/test_bug_61367-read/bad" in %s on line %d
+%s: DOMDocument::loadXML(): %Sfailed to load %s
 
 Warning: Attempt to read property "nodeValue" on null in %s on line %d

ext/libxml/tests/libxml_disable_entity_loader_2.phpt

@@ -39,6 +39,6 @@ bool(true)
 Deprecated: Function libxml_disable_entity_loader() is deprecated in %s on line %d
 bool(false)
 
-Warning: DOMDocument::loadXML(): %Sfailed to load external entity "%s" in %s on line %d
+%s: DOMDocument::loadXML(): %Sfailed to load %s
 bool(true)
 Done