Merge branch '3.4' into 4.4

* 3.4:
  [PropertyAccess] fix tests
  [WebProfilerBundle] fix test
  remove assertions that can never be reached
  [PropertyAccess] Improve message of unitialized property in php 7.4
  [HttpFoundation] Fixed session migration with custom cookie lifetime
  [Serializer] Remove unused variable
  Allow URL-encoded special characters in basic auth part of URLs
  [Serializer] Fix unitialized properties (from PHP 7.4.2) when serializing context for the cache key
  [Validator] Add missing Ukrainian and Russian translations
  No need to reconnect the bags to the session
  Support for Content Security Policy style-src-elem and script-src-elem in WebProfiler
  [PropertyInfo][ReflectionExtractor] Check the array mutator prefixes last when the property is singular

Author: nicolas-grekas

Tests/Debug/OptionsResolverIntrospectorTest.php

@@ -44,7 +44,7 @@ public function testGetDefaultThrowsOnNoConfiguredValue()
         $resolver->setDefined($option = 'foo');
 
         $debug = new OptionsResolverIntrospector($resolver);
-        $this->assertSame('bar', $debug->getDefault($option));
+        $debug->getDefault($option);
     }
 
     public function testGetDefaultThrowsOnNotDefinedOption()
@@ -54,7 +54,7 @@ public function testGetDefaultThrowsOnNotDefinedOption()
         $resolver = new OptionsResolver();
 
         $debug = new OptionsResolverIntrospector($resolver);
-        $this->assertSame('bar', $debug->getDefault('foo'));
+        $debug->getDefault('foo');
     }
 
     public function testGetLazyClosures()
@@ -75,7 +75,7 @@ public function testGetLazyClosuresThrowsOnNoConfiguredValue()
         $resolver->setDefined($option = 'foo');
 
         $debug = new OptionsResolverIntrospector($resolver);
-        $this->assertSame('bar', $debug->getLazyClosures($option));
+        $debug->getLazyClosures($option);
     }
 
     public function testGetLazyClosuresThrowsOnNotDefinedOption()
@@ -85,7 +85,7 @@ public function testGetLazyClosuresThrowsOnNotDefinedOption()
         $resolver = new OptionsResolver();
 
         $debug = new OptionsResolverIntrospector($resolver);
-        $this->assertSame('bar', $debug->getLazyClosures('foo'));
+        $debug->getLazyClosures('foo');
     }
 
     public function testGetAllowedTypes()