Wait for elasticsearch exit in packaging tests (#47242)

The archives stopElasticsearch utility method sends SIGTERM to the
elasticsearch process, but does not wait for it to exit. That can cause
subsequent tests to sometimes file. This commit adds wait logic to both
linux and windows for the stopElasticsearch method.

closes #44501

Author: rjernst

qa/os/src/test/java/org/elasticsearch/packaging/util/Archives.java

@@ -315,8 +315,8 @@ public static void stopElasticsearch(Installation installation) throws Exception
         assertThat(pid, not(isEmptyOrNullString()));
 
         final Shell sh = new Shell();
-        Platforms.onLinux(() -> sh.run("kill -SIGTERM " + pid));
-        Platforms.onWindows(() -> sh.run("Get-Process -Id " + pid + " | Stop-Process -Force"));
+        Platforms.onLinux(() -> sh.run("kill -SIGTERM " + pid + "; tail --pid=" + pid + " -f /dev/null"));
+        Platforms.onWindows(() -> sh.run("Get-Process -Id " + pid + " | Stop-Process -Force; Wait-Process -Id " + pid));
     }
 
 }