✅ N°6458 Improve ItopDataTestCase tests speed

What was measured :
- 1'54 with previous code (always doing a reset in tearDown)
- 1'44 without any ResetMetaModelQueyCacheGetObject call (but 3 tests are failing)
- 1'44 with new optin mechanism + don't call Logoff if no current user logged

tests/php-unit-tests/src/BaseTestCase/ItopDataTestCase.php

@@ -60,6 +60,13 @@ abstract class ItopDataTestCase extends ItopTestCase
 	// For cleanup
 	private $aCreatedObjects = [];
 
+	/**
+	 * @var bool When testing with silo, there are some cache we need to update on tearDown. Doing it all the time will cost too much, so it's opt-in !
+	 * @see tearDown
+	 * @see ResetMetaModelQueyCacheGetObject
+	 */
+	private $bIsUsingSilo = false;
+
 	/**
 	 * @var string Default environment to use for test cases
 	 */
@@ -133,9 +140,13 @@ abstract class ItopDataTestCase extends ItopTestCase
 		CMDBObject::SetCurrentChange(null);
 
 		// Leave the place clean
-		\UserRights::Logoff();
-		$this->SetNonPublicStaticProperty(UserRights::class, 'm_aCacheUsers', []);
-		$this->ResetMetaModelQueyCacheGetObject();
+		if (UserRights::IsLoggedIn()) {
+			UserRights::Logoff();
+		}
+		$this->SetNonPublicStaticProperty(UserRights::class, 'm_aCacheUsers', []); // we could have cached rollbacked instances
+		if ($this->bIsUsingSilo) {
+			$this->ResetMetaModelQueyCacheGetObject();
+		}
 
 		parent::tearDown();
 	}