title: Consolidate testng report from 4 mvn commands
body: <p>I need to run four mvn commands for my testng suites, in different environments, like so:</p>
  <p><code>mvn -Dfoo=bar -Denv=A test</code></p>
  <p>Same thing for env B, C and D.</p>
  <p>How to run commands, and consolidate testng results into one?</p>