RFR: 8271514: support JFR use of new ThreadsList::Iterator [v4]

[Daniel D.Daugherty]

On Wed, 22 Sep 2021 03:56:25 GMT, Daniel D. Daugherty <dcubed at openjdk.org> wrote:

>> A trivial fix to support JFR use of new ThreadsList::Iterator.
>> 
>> This fix was tested with Mach5 Tier[1-3].
>
> Daniel D. Daugherty has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains 13 commits:
> 
>  - Merge branch 'master' into JDK-8271514
>  - Merge branch 'master' into JDK-8271514
>  - Merge branch 'pull/4948' into JDK-8271514
>  - Merge branch 'master' into JDK-8271513
>  - Merge branch 'pull/4948' into JDK-8271514
>  - Merge branch 'pull/4671' into JDK-8271513
>  - kbarrett CR - simplify 'ThreadsList::Iterator::operator!=(Iterator i)'
>  - 8271514: support JFR use of new ThreadsList::Iterator
>  - 8271513: support JavaThreadIteratorWithHandle replacement by new ThreadsList::Iterator
>  - 8193559.kbarrett.part1 - Kim's proposed rewrite using newer C++ features.
>  - ... and 3 more: https://git.openjdk.java.net/jdk/compare/cbe57e86...76d44dcb

Rebased this project to the latest jdk/jdk baseline as of 2021.10.11 in the afternoon.

This PR needs a review from either @mgronlun or @egahlin since I'm changing
JFR code here.

The rebase has passed Mach5 Tier1 testing; Mach5 Tier[23] are in process.

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

PR: https://git.openjdk.java.net/jdk/pull/4949