Allow to disable AbandonedConnectionCleanupThread completely

[turbanoff]

Allow to disable AbandonedConnectionCleanupThread completely via system property com.mysql.disableAbandonedConnectionCleanup

to disable it add following string to JVM command line: -Dcom.mysql.disableAbandonedConnectionCleanup=true

[mysql-oca-bot]

Hi, thank you for submitting this pull request. In order to consider your code we need you to sign the Oracle Contribution Agreement (OCA). Please review the details and follow the instructions at http://www.oracle.com/technetwork/community/oca-486395.html
Please make sure to include your MySQL bug system user (email) in the returned form.
Thanks

[turbanoff]

I've signed OCA

[mysql-oca-bot]

Hi, there was no response to our request to sign an OCA or confirm the code is submitted under the terms of the OCA. As such this request will be closed.
Thanks

[turbanoff]

@mysql-oca-bot hello. As I said I've actually signed OCA.
Can you please reopen pull request?

[mysql-admin]

OCA in place but update missed by the script

[mysql-oca-bot]

Hi, thank you for your contribution. Please confirm this code is submitted under the terms of the OCA (Oracle's Contribution Agreement) you have previously signed by cutting and pasting the following text as a comment:
"I confirm the code being submitted is offered under the terms of the OCA, and that I am authorized to contribute it."
Thanks

[turbanoff]

I confirm the code being submitted is offered under the terms of the OCA, and that I am authorized to contribute it.

[mysql-oca-bot]

Hi, thank you for your contribution. Your code has been assigned to an internal queue. Please follow
bug http://bugs.mysql.com/bug.php?id=96870 for updates.
Thanks

[quaff]

#43 is related

[lefred]

Thank you for your contribution that has been added to 8.0.22: https://lefred.be/content/mysql-8-0-22-thank-you-for-the-contributions/