Skip change stream tests if connected to a standalone

Change streams require a replica set.

tests/DocumentationExamplesTest.php

@@ -4,6 +4,7 @@ namespace MongoDB\Tests;
 
 use MongoDB\Database;
 use MongoDB\Driver\Cursor;
+use MongoDB\Driver\Server;
 use MongoDB\Operation\DropCollection;
 use MongoDB\Operation\DropDatabase;
 
@@ -923,6 +924,10 @@ class DocumentationExamplesTest extends FunctionalTestCase
 
     public function testChangeStreamExample_1_4()
     {
+        if ($this->getPrimaryServer()->getType() === Server::TYPE_STANDALONE) {
+            $this->markTestSkipped('$changeStream is not supported on standalone servers');
+        }
+
         if (version_compare($this->getFeatureCompatibilityVersion(), '3.6', '<')) {
             $this->markTestSkipped('$changeStream is only supported on FCV 3.6 or higher');
         }

tests/Operation/WatchFunctionalTest.php

@@ -3,6 +3,7 @@
 namespace MongoDB\Tests\Operation;
 
 use MongoDB\Client;
+use MongoDB\Driver\Server;
 use MongoDB\Operation\DatabaseCommand;
 use MongoDB\Operation\InsertOne;
 use MongoDB\Operation\Watch;
@@ -13,6 +14,10 @@ class WatchFunctionalTest extends FunctionalTestCase
     {
         parent::setUp();
 
+        if ($this->getPrimaryServer()->getType() === Server::TYPE_STANDALONE) {
+            $this->markTestSkipped('$changeStream is not supported on standalone servers');
+        }
+
         if (version_compare($this->getFeatureCompatibilityVersion(), '3.6', '<')) {
             $this->markTestSkipped('$changeStream is only supported on FCV 3.6 or higher');
         }