RFR: 8218812: vmTestbase/nsk/jvmti/GetAllThreads/allthr001/TestDescription.java failed

[Daniil Titov]

Resending review request with corrected subject...

Please review a fix for this test that intermittently fails with Graal on.  

The problem here is that the test does two consequent calls to VirtualMachine.allThreads() and checks that the number of threads returned by these calls is the same. With Graal on there is a chance that a new JVMCI compiler thread could be started between these calls that makes test to fail. The fix temporary suspends the debuggee VM while these two calls to VirtualMachine.allThreads() are made. 

Webrev: http://cr.openjdk.java.net/~dtitov/8218464/webrev.01 
Bug: https://bugs.openjdk.java.net/browse/JDK-8218464 

Thanks!
--Daniil