MAGETWO-34612: Unit tests coverage build failure

- fixing reference to obsolete class

Author: mazhalai

dev/tests/static/testsuite/Magento/Test/Integrity/Layout/BlocksTest.php

@@ -97,7 +97,7 @@ public function getChildBlockDataProvider()
     {
         $result = [];
         foreach (Files::init()->getPhpFiles(true, false, true, false, false) as $file) {
-            $aliases = \Magento\Framework\Test\Utility\Classes::getAllMatches(
+            $aliases = \Magento\Framework\App\Utility\Classes::getAllMatches(
                 file_get_contents($file),
                 '/\->getChildBlock\(\'([^\']+)\'\)/x'
             );