Fix trivial PyPy failures

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### Description

Fixes: #13274
References: #9154

There were two relatively causes to some of the ~21 failures on PyPy:
- weakrefs may be deleted but the objects not finalized on PyPy. This manifests as `ref.obj() is None` I added a test for the `release()` case that also failed on CPython before the fix.
- a condition added in 2022 for missing sqllite3 behaviour is no longer necessary, and is now causing a failure

In order to run the changes in CI, I added PyPy to the PR CI run. Before merging I will revert that change. There are still a number of failures with PyPy around different error messages, different inspect.signatures and one sticky problem with the pure-python datetime.py that actually comes from CPython. I will continue to work on them, but they are not specific to sqlalchemy.

Note the CI run is ~6 minutes where the CPython ones are ~3 minutes. This is expected, since PyPy's JIT does not kick in on short tests, and the base compiler is about 2x slower.

### Checklist
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This pull request is:

- [ ] A documentation / typographical / small typing error fix
	- Good to go, no issue or tests are needed
- [x] A short code fix
	- please include the issue number, and create an issue if none exists, which
	  must include a complete example of the issue.  one line code fixes without an
	  issue and demonstration will not be accepted.
	- Please include: `Fixes: #<issue number>` in the commit message
	- please include tests.   one line code fixes without tests will not be accepted.
- [ ] A new feature implementation
	- please include the issue number, and create an issue if none exists, which must
	  include a complete example of how the feature would look.
	- Please include: `Fixes: #<issue number>` in the commit message
	- please include tests.

**Have a nice day!**

Closes: #13276
Pull-request: https://github.com/sqlalchemy/sqlalchemy/pull/13276
Pull-request-sha: 00472f32f64827325f071150e8b6ecf1fbe9f22e

Change-Id: Id5d4ba37cf8db2345a948f973d7b1710910359a1