Seen in nightlies.

Extracted from logs:

debugee.stderr> **> debuggee: debuggee exits
debugger> TESTING ENDS
debugger> Waiting for debuggee's exit...
EventHandler> waitForVMDisconnect
EventHandler> Received event set with policy = SUSPEND_NONE
EventHandler> Event: VMDeathEventImpl req null
EventHandler> receieved VMDeath
EventHandler> Removing listener nsk.share.jdi.EventHandler$3@4d405ef7
EventHandler> Received event set with policy = SUSPEND_NONE
EventHandler> Event: VMDisconnectEventImpl req null
EventHandler> receieved VMDisconnect
EventHandler> Removing listener nsk.share.jdi.EventHandler$4@6193b845
EventHandler> finished
EventHandler> waitForVMDisconnect: done
debugger> Event handler thread exited.
# ERROR: debugger> Debuggee returned unexpected exit status: 0


#>
#> SUMMARY: Following errors occured
#> during test execution:
#>
# ERROR: debugger> Debuggee returned unexpected exit status: 0