RFR: 8322420: [Linux] cgroup v2: Limits in parent nested control groups are not detected [v6]

[Jan Kratochvil]

> The testcase requires root permissions.

Jan Kratochvil has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains 15 additional commits since the last revision:

 - Merge branch 'master' into master-cgroup
 - Fail reading memory.stat only once
 - Extend cgroup test
 - Add read_hierarchical_memsw_limit
 - Add cgroup2 hierarchical_memory_limit support, kernel patch not yet submitted
 - Remove unneeded jdk.test.lib.helpers.ClassFileInstaller
 - Fix test/jdk/jdk/internal/platform/cgroup/ testcases regression
 - Fix cgroup1 hierarchical limit reading
 - Fix the testcase for cgroup1
 - NestedCgroup: Better error reporting
 - ... and 5 more: https://git.openjdk.org/jdk/compare/d82f199c...9fe67514

-------------

Changes:
  - all: https://git.openjdk.org/jdk/pull/17198/files
  - new: https://git.openjdk.org/jdk/pull/17198/files/0c912965..9fe67514

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=17198&range=05
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=17198&range=04-05

  Stats: 20562 lines in 1320 files changed: 8514 ins; 1856 del; 10192 mod
  Patch: https://git.openjdk.org/jdk/pull/17198.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/17198/head:pull/17198

PR: https://git.openjdk.org/jdk/pull/17198