MAGETWO-34174: CI builds stabilization

- Passed non-empty string to __() function in ShellTest;

Author: Dmytro Poperechnyy

dev/tests/unit/testsuite/Magento/Indexer/Model/ShellTest.php

@@ -175,12 +175,20 @@ public function testRunException($args)
         }
         if ($args == 'reindexall') {
             $indexerMock->expects($this->any())->method('reindexAll')->will(
-                $this->throwException(new \Magento\Framework\Exception\LocalizedException(__('')))
+                $this->throwException(
+                    new \Magento\Framework\Exception\LocalizedException(
+                        __('Something went wrong during reindexing all.')
+                    )
+                )
             );
         }
         if ($args == '--mode-schedule') {
             $indexerMock->expects($this->any())->method('turnViewOn')->will(
-                $this->throwException(new \Magento\Framework\Exception\LocalizedException(__('')))
+                $this->throwException(
+                    new \Magento\Framework\Exception\LocalizedException(
+                        __('Something went wrong during turning view on.')
+                    )
+                )
             );
         }
         if ($args == '--reindex=price') {