hg: jdk/sandbox: let TestLargeRootSet retry on failure

[markus.gronlund at oracle.com]

Changeset: db26cf04e6ab
Author:    mgronlun
Date:      2019-09-30 14:27 +0200
URL:       https://hg.openjdk.java.net/jdk/sandbox/rev/db26cf04e6ab

let TestLargeRootSet retry on failure

! test/jdk/jdk/jfr/event/oldobject/TestLargeRootSet.java