RFR: 8231296: ZGC: vmTestbase/nsk/jvmti/Allocate/alloc001/ fails

[Per Liden]

Please review this one-liner to disable 
vmTestbase/nsk/jvmti/Allocate/alloc001 when using ZGC. The root problem 
is that ZGC doesn't properly respect address space limitations 
(RLIMIT_AS). This test will be re-enabled again as part of fixing 
https://bugs.openjdk.java.net/browse/JDK-8231552

Bug: https://bugs.openjdk.java.net/browse/JDK-8231296
Webrev: http://cr.openjdk.java.net/~pliden/8231296/webrev.0

/Per