Run virtual/stress/Skynet with -Xnocompressedrefs

Skynet is a stress benchmark, which exceeds the below 4G capacity
of -Xcompressedrefs. The current workaround is to use
-Xnocompressedrefs where memory can be allocated outside the 4G
boundary.

To run Skynet with -Xcompressedrefs, the following features will be
needed:
- Move unmounted continuation stacks out of the low memory area.
- Improve performance of the sub-4G allocator so that it doesn't
  regress under high memory usage.

Depends on eclipse-openj9/openj9#18251

Related: eclipse-openj9/openj9#16728

Related: eclipse-openj9/openj9#15781

Signed-off-by: Babneet Singh <sbabneet@ca.ibm.com>

test/jdk/java/lang/Thread/virtual/stress/Skynet.java

@@ -26,14 +26,14 @@
  * @summary Stress test virtual threads with a variation of the Skynet 1M benchmark
  * @requires vm.continuations
  * @requires !vm.debug | vm.gc != "Z"
- * @run main/othervm/timeout=300 -Xmx1g Skynet
+ * @run main/othervm/timeout=300 -Xmx1g -Xnocompressedrefs Skynet
  */
 
 /*
  * @test id=ZSinglegen
  * @requires vm.debug == true & vm.continuations
  * @requires vm.gc.ZSinglegen
- * @run main/othervm/timeout=300 -XX:+UnlockDiagnosticVMOptions
+ * @run main/othervm/timeout=300 -XX:+UnlockDiagnosticVMOptions -Xnocompressedrefs
  * -XX:+UseZGC -XX:-ZGenerational
  * -XX:+ZVerifyOops -XX:ZCollectionInterval=0.01 -Xmx1g Skynet
  */
@@ -42,7 +42,7 @@
  * @test id=ZGenerational
  * @requires vm.debug == true & vm.continuations
  * @requires vm.gc.ZGenerational
- * @run main/othervm/timeout=300 -XX:+UnlockDiagnosticVMOptions
+ * @run main/othervm/timeout=300 -XX:+UnlockDiagnosticVMOptions -Xnocompressedrefs
  * -XX:+UseZGC -XX:+ZGenerational
  * -XX:+ZVerifyOops -XX:ZCollectionInterval=0.01 -Xmx1g Skynet
  */