On linux-aarch64 there have been a couple of failures due to:

Exception: java.lang.RuntimeException: 'CounterData' missing from stdout/stderr

In both cases the printmdo output was empty:

Output:
hsdb> hsdb> + verbose true
hsdb> + printmdo -a
hsdb> + printall
<printall output follows>

So far this has only happened on linux-aarch64 (both debug and product). In both cases the flags being used were:

   "-Xcomp -XX:TieredStopAtLevel=1"

Possibly aarch64 doesn't support this, which I believe is suppose to simulate "client" compiler behavior.