Merge branch '4.4' into 5.2

* 4.4:
  Simplify some code with null coalesce operator

Author: derrabus

Firewall/RememberMeListener.php

@@ -49,7 +49,7 @@ public function __construct(TokenStorageInterface $tokenStorage, RememberMeServi
         $this->logger = $logger;
         $this->dispatcher = $dispatcher;
         $this->catchExceptions = $catchExceptions;
-        $this->sessionStrategy = null === $sessionStrategy ? new SessionAuthenticationStrategy(SessionAuthenticationStrategy::MIGRATE) : $sessionStrategy;
+        $this->sessionStrategy = $sessionStrategy ?? new SessionAuthenticationStrategy(SessionAuthenticationStrategy::MIGRATE);
     }
 
     /**

Tests/Firewall/ExceptionListenerTest.php

@@ -99,7 +99,7 @@ public function testAccessDeniedExceptionFullFledgedAndWithoutAccessDeniedHandle
         $listener->onKernelException($event);
 
         $this->assertNull($event->getResponse());
-        $this->assertSame(null === $eventException ? $exception : $eventException, $event->getThrowable()->getPrevious());
+        $this->assertSame($eventException ?? $exception, $event->getThrowable()->getPrevious());
     }
 
     /**
@@ -122,7 +122,7 @@ public function testAccessDeniedExceptionFullFledgedAndWithoutAccessDeniedHandle
 
         $this->assertEquals('Unauthorized', $event->getResponse()->getContent());
         $this->assertEquals(401, $event->getResponse()->getStatusCode());
-        $this->assertSame(null === $eventException ? $exception : $eventException, $event->getThrowable()->getPrevious());
+        $this->assertSame($eventException ?? $exception, $event->getThrowable()->getPrevious());
     }
 
     /**
@@ -139,7 +139,7 @@ public function testAccessDeniedExceptionFullFledgedAndWithAccessDeniedHandlerAn
         $listener->onKernelException($event);
 
         $this->assertEquals('error', $event->getResponse()->getContent());
-        $this->assertSame(null === $eventException ? $exception : $eventException, $event->getThrowable()->getPrevious());
+        $this->assertSame($eventException ?? $exception, $event->getThrowable()->getPrevious());
     }
 
     /**
@@ -156,7 +156,7 @@ public function testAccessDeniedExceptionNotFullFledged(\Exception $exception, \
         $listener->onKernelException($event);
 
         $this->assertEquals('OK', $event->getResponse()->getContent());
-        $this->assertSame(null === $eventException ? $exception : $eventException, $event->getThrowable()->getPrevious());
+        $this->assertSame($eventException ?? $exception, $event->getThrowable()->getPrevious());
     }
 
     public function testLogoutException()