DO NOT MERGE: Add validation for eternal enities

https://bugzilla.gnome.org/show_bug.cgi?id=780691

Bug: 36556310
Change-Id: I9450743e167c3c73af5e4071f3fc85e81d061648
(cherry picked from commit bef9af3d89d241bcb518c20cba6da2a2fd9ba049)

xmlDocPtr xmlRecoverMemory(const char *buffer, int size) {
 return(xmlSAXParseMemory(NULL, buffer, size, 1));
}

xmlDocPtr xmlRecoverMemory(const char *buffer, int size) {
 return(xmlSAXParseMemory(NULL, buffer, size, 1));
}
