Compiler should not need to know how to construct AST nodes #123881
Description
There is one place in the compiler where it copies a bit of AST and modifies it to add a base class to generic classes.
It would be nice if the compiler didn't need to know how to do this.
Linked PRs
- gh-123881: make compiler add the .generic_base base class without constructing AST nodes #123883
- gh-123881: Add additional test coverage for PEP 695 edge cases #123886
- [3.13] gh-123881: Add additional test coverage for PEP 695 edge cases (GH-123886) #123890
- [3.12] gh-123881: Add additional test coverage for PEP 695 edge cases (GH-123886) #123891