Improve test reliability

Author: fredden

app/code/Magento/Catalog/Test/Mftf/Test/StorefrontVerifyProductAfterPartialReindexOnSeveralWebsitesTest.xml

@@ -82,7 +82,10 @@
         </actionGroup>
 
         <!-- Run cron -->
-        <magentoCLI command="cron:run" stepKey="runCron"/>
+        <!-- We need the 'indexer_update_all_views' job to run. This is the best
+            way we can make that happen, but there is no guarantee that there is
+            such a job already scheduled in the queue. -->
+        <magentoCLI command="cron:run --group=index --bootstrap=standaloneProcessStarted=1" stepKey="runCron"/>
 
         <!-- Check product is present in category after cron run -->
         <actionGroup ref="AssertProductInStorefrontCategoryPage" stepKey="assertProductInStorefront1">