[jdk11u-dev] RFR: 8284102: [TESTBUG] Retroactively add regression test for JDK-8272124

[Severin Gehwolf]

This adds a regression test for the fix originally backported when no cgroups v2 support was present (and, thus, test infra wasn't there either). The test passes. If the fix regets reverted it fails (as expected).

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Depends on: https://git.openjdk.java.net/jdk11u-dev/pull/1020

Commit messages:
 - 8284102: [TESTBUG] Retroactively add regression test for JDK-8272124

Changes: https://git.openjdk.java.net/jdk11u-dev/pull/1056/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk11u-dev&pr=1056&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8284102
  Stats: 53 lines in 1 file changed: 53 ins; 0 del; 0 mod
  Patch: https://git.openjdk.java.net/jdk11u-dev/pull/1056.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk11u-dev pull/1056/head:pull/1056

PR: https://git.openjdk.java.net/jdk11u-dev/pull/1056