RFR: 8357830: JfrVframeStream::_cont_entry shadows super-class field

[Markus Grönlund]

Greetings,

SonarCloud has a report that `JfrVframeStream::_cont_entry` shadows the super-class field of the same name.

Fixed and inlined the constructor.

Testing: jdk_jfr

Thanks
Markus

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Commit messages:
 - avoid shadowing super-class field _cont_entry and inline

Changes: https://git.openjdk.org/jdk/pull/25465/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=25465&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8357830
  Stats: 92 lines in 3 files changed: 35 ins; 56 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/25465.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/25465/head:pull/25465

PR: https://git.openjdk.org/jdk/pull/25465