The following test timed out during compilation with ZGC in the JDK17 CI:

vmTestbase/gc/memory/UniThread/Circular1/Circular1.java

Here's a snippet from the log file:

#section:compile
----------messages:(8/372)*----------
command: compile C:\\ade\\mesos\\work_dir\\jib-master\\install\\jdk-17+15-1161\\src.full\\open\\test\\hotspot\\jtreg\\vmTestbase\\gc\\memory\\UniThread\\Circular1\\Circular1.java
reason: .class file out of date or does not exist
Mode: agentvm
Agent id: 12
Timeout refired 480 times
Timeout information:
--- Timeout information end.
elapsed time (seconds): 751.921
----------configuration:(14/1434)*----------
Boot Layer (javac runtime environment)
  class path: C:\\ade\\mesos\\work_dir\\jib-master\\install\\jtreg\\5.1\\b01\\bundles\\jtreg_bin-5.1.zip\\jtreg\\lib\\javatest.jar
              C:\\ade\\mesos\\work_dir\\jib-master\\install\\jtreg\\5.1\\b01\\bundles\\jtreg_bin-5.1.zip\\jtreg\\lib\\jtreg.jar
  patch: java.base T:\\testoutput\\test-support\\jtreg_open_test_hotspot_jtreg_vmTestbase_vm_gc_misc\\patches\\java.base

javac compilation environment
  source path: C:\\ade\\mesos\\work_dir\\jib-master\\install\\jdk-17+15-1161\\src.full\\open\\test\\hotspot\\jtreg\\vmTestbase\\gc\\memory\\UniThread\\Circular1
               C:\\ade\\mesos\\work_dir\\jib-master\\install\\jdk-17+15-1161\\src.full\\open\\test\\hotspot\\jtreg\\vmTestbase
               C:\\ade\\mesos\\work_dir\\jib-master\\install\\jdk-17+15-1161\\src.full\\open\\test\\lib
  class path: C:\\ade\\mesos\\work_dir\\jib-master\\install\\jdk-17+15-1161\\src.full\\open\\test\\hotspot\\jtreg\\vmTestbase\\gc\\memory\\UniThread\\Circular1
               T:\\testoutput\\test-support\\jtreg_open_test_hotspot_jtreg_vmTestbase_vm_gc_misc\\classes\\0\\vmTestbase\\gc\\memory\\UniThread\\Circular1\\Circular1.d
               T:\\testoutput\\test-support\\jtreg_open_test_hotspot_jtreg_vmTestbase_vm_gc_misc\\classes\\0\\vmTestbase
               T:\\testoutput\\test-support\\jtreg_open_test_hotspot_jtreg_vmTestbase_vm_gc_misc\\classes\\0\\test\\lib

----------rerun:(42/6608)*----------

<snip>

result: Error. Agent error: java.lang.Exception: Agent 12 timed out with a timeout of 480 seconds; check console log for any additional details

Please note that this is a timeout DURING COMPILATION which
is strange. Since this is a GC test, I'm starting this issue in
hotspot/gc for initial triage.