MAGETWO-94083: Impossible get information about static errors on PR

- create empty report file for the case when there no php and phtml files

Author: melnikovi

dev/tests/static/testsuite/Magento/Test/Php/LiveCodeTest.php

@@ -256,6 +256,9 @@ private function getFullWhitelist()
         }
     }
 
+    /**
+     * Test code quality using phpcs
+     */
     public function testCodeStyle()
     {
         $isFullScan = defined('TESTCODESTYLE_IS_FULL_SCAN') && TESTCODESTYLE_IS_FULL_SCAN === '1';
@@ -273,6 +276,9 @@ public function testCodeStyle()
         );
     }
 
+    /**
+     * Test code quality using phpmd
+     */
     public function testCodeMess()
     {
         $reportFile = self::$reportDir . '/phpmd_report.txt';
@@ -301,6 +307,9 @@ public function testCodeMess()
         }
     }
 
+    /**
+     * Test code quality using phpcpd
+     */
     public function testCopyPaste()
     {
         $reportFile = self::$reportDir . '/phpcpd_report.xml';