[11u] RFR: 8254854: [cgroups v1] Metric limits not properly detected on some join controller combinations

[Severin Gehwolf]

Hi,

Could I please get a review for this follow-up fix to JDK-8217766 which
is in OpenJDK 11 since 11.0.5. The fix for JDK-8217766 was incomplete.
The JDK 15 patch didn't apply cleanly due to no cgroups v2 support in
JDK 11u. I've basically reworked the patch for 11u. The port was fairly
straight-forward, though.

1)
Changes in src/java.base/linux/classes/jdk/internal/platform/cgroupv1/CgroupV1Subsystem.java
needed to be done in src/java.base/linux/classes/jdk/internal/platform/cgroupv1/Metrics.java

2)
Function names changed from setSubSystemControllerPath() JDK 15+ to
setSubSystemPath() in JDK 11.

Bug: https://bugs.openjdk.java.net/browse/JDK-8254854
webrev: https://cr.openjdk.java.net/~sgehwolf/webrevs/JDK-8254854/01/webrev/

Testing: tier 1 and Linux container tests on x86_64 (cgroups v1);
         manual testing of the fix[1]

Thoughts?

Thanks,
Severin

[1] https://bugs.openjdk.java.net/browse/JDK-8254854?focusedCommentId=14377579&page=com.atlassian.jira.plugin.system.issuetabpanels%3Acomment-tabpanel#comment-14377579