Revert "Tune maximum thread count for streaming dataflow worker executor dynamically.

[MelodyShen]

[Verification in progress. It's not ready to be merged yet.]

This reverts commit d499074.

Performance regression was detected. Revert the suspicious change to see if the regression is fixed.

R: @damccorm @tudorm @scwhittle

---

Thank you for your contribution! Follow this checklist to help us incorporate your contribution quickly and easily:

• Mention the appropriate issue in your description (for example: addresses #123), if applicable. This will automatically add a link to the pull request in the issue. If you would like the issue to automatically close on merging the pull request, comment fixes #<ISSUE NUMBER> instead.
• Update CHANGES.md with noteworthy changes.
• If this contribution is large, please file an Apache Individual Contributor License Agreement.

See the Contributor Guide for more tips on how to make review process smoother.

To check the build health, please visit https://github.com/apache/beam/blob/master/.test-infra/BUILD_STATUS.md

GitHub Actions Tests Status (on master branch)

See CI.md for more information about GitHub Actions CI or the workflows README to see a list of phrases to trigger workflows.

[MelodyShen]

Hi @damccorm @tudorm here is the pr to revert the #30439 that caused performance regression. Would you mind taking a look? Thanks!

[github-actions]

Assigning reviewers. If you would like to opt out of this review, comment assign to next reviewer:

R: @tvalentyn added as fallback since no labels match configuration

Available commands:

• stop reviewer notifications - opt out of the automated review tooling
• remind me after tests pass - tag the comment author after tests pass
• waiting on author - shift the attention set back to the author (any comment or push by the author will return the attention set to the reviewers)

The PR bot will only process comments in the main thread (not review comments).

[tvalentyn]

do you need the revert to be merged in order to test performance change?

[MelodyShen]

do you need the revert to be merged in order to test performance change?

We plan to create an import cl and let the performance tests run against head during the weekends. And later merge the pr if we confirm that this change causes the regression. It seems the performance went back to normal currently so we are still observing it.
Mark it as non-mergeable in the description for now. Thank you!