Test gc/shenandoah/generational/TestOldGrowthTriggers.java intermittent fails "'Trigger (Old): Old has overgrown' missing from stdout/stderr" with default JVM options by fastdebug build on linux-aarch64. The failure probability about 1/100.

Should we add '@key intermittent' tag for this test until the root cause has been fixed. The '@key intermittent' tag make some test infrasture disable or rerun this test automaticly when it's intermittent fails.