Symfony version(s) affected: 5+

Description
Before upgrading to 5 version, I used several static::createClient() in tests, which worked fine, but was broke with version 5.

Reading Documentation one could be assured, that multiple static::createClient() are fine and should work, which is false.

->insulate(); does not help either.

How to reproduce

$harry = static::createClient();
$sally = static::createClient();

Possible Solution
Either revert the change, that broke this, or update the documentation with the details on how to actually
...create several clients:
$harry = static::createClient();
$sally = static::createClient();
This works...

Additional context
This issue is essentially the same as #35031, but that issue was closed as fixed, whereas in fact it is not fixed at all.