Merge branch '3.4' into 4.0

* 3.4:
  fixed wrong merge
  Tweak message to be Flex friendly
  [Routing] fixed tests
  Fixing wrong class_exists on interface
  Preserve percent-encoding in URLs when performing redirects in the UrlMatcher
  [Console] Fix a bug when passing a letter that could be an alias
  add missing validation options to XSD file
  Take advantage of AnnotationRegistry::registerUniqueLoader
  [DI] Optimize Container::get() for perf
  fix merge
  Fix tests
  Refactoring tests.

Author: fabpot

Tests/ConstraintViolationListTest.php

@@ -89,16 +89,16 @@ public function testArrayAccess()
         $this->list[] = $violation;
 
         $this->assertSame($violation, $this->list[0]);
-        $this->assertTrue(isset($this->list[0]));
+        $this->assertArrayHasKey(0, $this->list);
 
         unset($this->list[0]);
 
-        $this->assertFalse(isset($this->list[0]));
+        $this->assertArrayNotHasKey(0, $this->list);
 
         $this->list[10] = $violation;
 
         $this->assertSame($violation, $this->list[10]);
-        $this->assertTrue(isset($this->list[10]));
+        $this->assertArrayHasKey(10, $this->list);
     }
 
     public function testToString()