Should fix issue #5979
We could also trim code issues when writing to baseline, but I think
that's a minor BC break, so probably shouldn't happen until Psalm 9.
Fixesvimeo/psalm#5405
Requires new patch release.
This PR reverts changes to the signature of `IssueBuffer::finish()` and
introduces separate method to be used to capture `$_SERVER`
* Wrap entrypoints into IIFE to protect their variables
Fixesvimeo/psalm#5359
* Add tests for Psalm variable isolation
* Capture environment before registering autoloader