Tier 2 optimizer: constant propagate through attribute loads

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Feature or enhancement

Proposal:

Now that we have type versions installed in #119258 . We can use the information to constant propagate through attribute loads.

This means something like

dict.fromkeys()

becomes the same as

dict_fromkeys()

Note: this is just a constant load, not an attribute lookup!

Has this already been discussed elsewhere?

No response given

Links to previous discussion of this feature:

No response

Linked PRs

• gh-120323: Constant fold entire attribute loads #120344
• gh-120323: Remove class check for redundant _CHECK_ATTR_CLASS #121002

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CC @saulshanabrook this is building off your work!

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Nevermind, I forgot we yet to have a specialization for builtin class loads, so we can't do this until we add the tier 1 specialization.

For now, I can add this for tier 2 just for Python classes.