[jdk17u-dev] RFR: 8284977: MetricsTesterCgroupV2.getLongValueEntryFromFile fails when named value doesn't exist

[Matthias Baesken]

8284977: MetricsTesterCgroupV2.getLongValueEntryFromFile fails when named value doesn't exist

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Commit messages:
 - Backport 444a0d98ac06ab043e3b11281234fd515abff302

Changes: https://git.openjdk.org/jdk17u-dev/pull/532/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk17u-dev&pr=532&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8284977
  Stats: 5 lines in 1 file changed: 5 ins; 0 del; 0 mod
  Patch: https://git.openjdk.org/jdk17u-dev/pull/532.diff
  Fetch: git fetch https://git.openjdk.org/jdk17u-dev pull/532/head:pull/532

PR: https://git.openjdk.org/jdk17u-dev/pull/532