RFR: 8362573: Incorrect weight of the first ObjectAllocationSample JFR event (regression) [v4]

[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

Markus Grönlund has updated the pull request incrementally with one additional commit since the last revision:

  missing imports in test

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/26900/files
  - new: https://git.openjdk.org/jdk/pull/26900/files/2fda62f7..95516294

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=26900&range=03
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=26900&range=02-03

  Stats: 2 lines in 1 file changed: 2 ins; 0 del; 0 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