Merge branch '2.8' into 3.2

* 2.8:
  Update to PHPUnit namespaces
  Minor typo fix messsagesData -> messagesData
  remove translation data collector when not usable

Tests/ApcClassLoaderTest.php

@@ -11,10 +11,11 @@
 
 namespace Symfony\Component\ClassLoader\Tests;
 
+use PHPUnit\Framework\TestCase;
 use Symfony\Component\ClassLoader\ApcClassLoader;
 use Symfony\Component\ClassLoader\ClassLoader;
 
-class ApcClassLoaderTest extends \PHPUnit_Framework_TestCase
+class ApcClassLoaderTest extends TestCase
 {
     protected function setUp()
     {

Tests/ClassCollectionLoaderTest.php

@@ -11,6 +11,7 @@
 
 namespace Symfony\Component\ClassLoader\Tests;
 
+use PHPUnit\Framework\TestCase;
 use Symfony\Component\ClassLoader\ClassCollectionLoader;
 use Symfony\Component\ClassLoader\Tests\Fixtures\DeclaredClass;
 use Symfony\Component\ClassLoader\Tests\Fixtures\WarmedClass;
@@ -20,7 +21,7 @@ require_once __DIR__.'/Fixtures/ClassesWithParents/CInterface.php';
 require_once __DIR__.'/Fixtures/ClassesWithParents/B.php';
 require_once __DIR__.'/Fixtures/ClassesWithParents/A.php';
 
-class ClassCollectionLoaderTest extends \PHPUnit_Framework_TestCase
+class ClassCollectionLoaderTest extends TestCase
 {
     public function testTraitDependencies()
     {

Tests/ClassLoaderTest.php

@@ -11,9 +11,10 @@
 
 namespace Symfony\Component\ClassLoader\Tests;
 
+use PHPUnit\Framework\TestCase;
 use Symfony\Component\ClassLoader\ClassLoader;
 
-class ClassLoaderTest extends \PHPUnit_Framework_TestCase
+class ClassLoaderTest extends TestCase
 {
     public function testGetPrefixes()
     {

Tests/ClassMapGeneratorTest.php

@@ -11,9 +11,10 @@
 
 namespace Symfony\Component\ClassLoader\Tests;
 
+use PHPUnit\Framework\TestCase;
 use Symfony\Component\ClassLoader\ClassMapGenerator;
 
-class ClassMapGeneratorTest extends \PHPUnit_Framework_TestCase
+class ClassMapGeneratorTest extends TestCase
 {
     /**
      * @var string|null

Tests/Psr4ClassLoaderTest.php

@@ -11,9 +11,10 @@
 
 namespace Symfony\Component\ClassLoader\Tests;
 
+use PHPUnit\Framework\TestCase;
 use Symfony\Component\ClassLoader\Psr4ClassLoader;
 
-class Psr4ClassLoaderTest extends \PHPUnit_Framework_TestCase
+class Psr4ClassLoaderTest extends TestCase
 {
     /**
      * @param string $className