RFR: 8362573: Incorrect weight of the first ObjectAllocationSample JFR event (regression)

[Markus Grönlund]

Greetings,

Fix to ensure that the ObjectAllocationSample event sample weight property is initialized correctly when the event is enabled.

The previous clearing logic has been integrated into the existing thread iteration as part of the notify process, to avoid double passes. In addition, clearing and the event only apply to the set of JavaThreads.

This time also includes a regression test.

Testing: jdk_jfr

Thanks
Markus

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Commit messages:
 - 8362573

Changes: https://git.openjdk.org/jdk/pull/26900/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=26900&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8362573
  Stats: 194 lines in 7 files changed: 133 ins; 30 del; 31 mod
  Patch: https://git.openjdk.org/jdk/pull/26900.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/26900/head:pull/26900

PR: https://git.openjdk.org/jdk/pull/26900