Merge branch '5.4' into 6.2

* 5.4:
  relax assertions for ICU 72.1
  [Validator] Fix regression with class metadatada on parent classes
  [VarExporter] Fix exporting classes with __serialize() but not __unserialize()
  [HttpFoundation][HttpKernel] Fix deprecations when `Content-Type` is `null`

Author: derrabus

Tests/Extension/Core/DataTransformer/DateTimeToLocalizedStringTransformerTest.php

@@ -124,7 +124,7 @@ public function testTransformToDifferentLocale()
 
         $transformer = new DateTimeToLocalizedStringTransformer('UTC', 'UTC');
 
-        $this->assertEquals('Feb 3, 2010, 4:05 AM', $transformer->transform($this->dateTime));
+        $this->assertMatchesRegularExpression('/^Feb 3, 2010, 4:05\s+AM$/u', $transformer->transform($this->dateTime));
     }
 
     public function testTransformEmpty()

Tests/Extension/Core/Type/DateTimeTypeTest.php

@@ -530,7 +530,7 @@ public function testSingleTextWidgetWithCustomNonHtml5Format()
         ]);
         $view = $form->createView();
 
-        $this->assertSame('2/13/19, 7:12:13 PM', $view->vars['value']);
+        $this->assertMatchesRegularExpression('#^2/13/19, 7:12:13\s+PM$#u', $view->vars['value']);
     }
 
     public function testDateTypeChoiceErrorsBubbleUp()