PHPC-431: Add the testcase from the report

Author: bjori

tests/standalone/manager-as-singleton.phpt

@@ -0,0 +1,64 @@
+--TEST--
+PHPC-431: Segfault when using Manager through singleton class
+--SKIPIF--
+<?php require __DIR__ . "/../utils/basic-skipif.inc"; ?>
+--FILE--
+<?php
+use MongoDB\Driver\Manager;
+use MongoDB\Driver\Query;
+use MongoDB\Driver\ReadPreference;
+ 
+require_once __DIR__ . "/../utils/basic.inc";
+
+ 
+class Database {
+    private $Database;
+    private static $Instance;
+ 
+    public function __construct() {
+        $Manager = new Manager(STANDALONE, array(), array());
+        $this->Database = $Manager;
+    }
+ 
+    public static function getInstance() {
+        if (static::$Instance == null) {
+            static::$Instance = new Database();
+        }
+ 
+        return static::$Instance;
+    }
+ 
+    public function query($scheme, $query) {
+        return $this->Database->executeQuery($scheme, $query, new ReadPreference(ReadPreference::RP_PRIMARY));
+    }
+}
+ 
+class App {
+    public function run() {
+        $db = Database::getInstance();
+        
+        $query = new Query(array());
+        $cursor = $db->query(DATABASE_NAME . ".scheme_info", $query);
+ 
+        foreach ($cursor as $document) {
+            echo $document->value;
+        }
+ 
+        $query = new Query(array());
+        $cursor = $db->query(DATABASE_NAME . ".domain", $query);
+ 
+        foreach ($cursor as $document) {
+            echo $document->hostname;
+        }
+    }
+}
+ 
+$App = new App();
+$App->run();
+echo "All done\n";
+?>
+===DONE===
+<?php exit(0); ?>
+--EXPECT--
+All done
+===DONE===