Merge branch '6.0' into 6.1

* 6.0:
  Fix double authentication via RememberMe resulting in wrong RememberMe cookie being set in client
  [Security] Fix legacy impersonation system
  Fix global state pollution between tests run with ApplicationTester
  µcs fix
  [Messenger] Do not log the message object itself
  [Intl] Fix the IntlDateFormatter::formatObject signature

Author: fabpot

Tests/Dumper/PhpDumperTest.php

@@ -814,7 +814,7 @@ public function testLazyArgumentProvideGenerator()
             switch (++$i) {
                 case 0:
                     $this->assertEquals('k1', $k);
-                    $this->assertInstanceOf(\stdCLass::class, $v);
+                    $this->assertInstanceOf(\stdClass::class, $v);
                     break;
                 case 1:
                     $this->assertEquals('k2', $k);