gh-87092: expose the compiler's codegen to python for unit tests

[iritkatriel]

With this we can run just codegen from python, and get the un-optimized instruction sequence for an AST.

• Issue: Split compiler into code-gen, optimizer and assembler. #87092

[bedevere-bot]

🤖 New build scheduled with the buildbot fleet by @iritkatriel for commit a2a1c17 🤖

If you want to schedule another build, you need to add the ":hammer: test-with-buildbots" label again.

[bedevere-bot]

🤖 New build scheduled with the buildbot fleet by @iritkatriel for commit 3c1c647 🤖

If you want to schedule another build, you need to add the ":hammer: test-with-buildbots" label again.

[bedevere-bot]

🤖 New build scheduled with the buildbot fleet by @iritkatriel for commit d98f150 🤖

If you want to schedule another build, you need to add the ":hammer: test-with-buildbots" label again.

[bedevere-bot]

🤖 New build scheduled with the buildbot fleet by @iritkatriel for commit 00aea64 🤖

If you want to schedule another build, you need to add the ":hammer: test-with-buildbots" label again.

[bedevere-bot]

🤖 New build scheduled with the buildbot fleet by @iritkatriel for commit ab3f67c 🤖

If you want to schedule another build, you need to add the ":hammer: test-with-buildbots" label again.

[markshannon]

This is a nice improvement.
I have a few questions and comments.

[markshannon]

Does this (or the other functions) need to be an API function?

[iritkatriel]

Can _testinternalcapi import them otherwise?

[markshannon]

I think so, that why it has "internal" in the name.
It defines Py_BUILD_CORE_BUILTIN

[iritkatriel]

It doesn't seem to work:

[ERROR] _testinternalcapi failed to import: dlopen(/Users/iritkatriel/src/cpython-654/build/lib.macosx-13.0-x86_64-3.12-pydebug/_testinternalcapi.cpython-312d-darwin.so, 0x0002): symbol not found in flat namespace '__PyCompile_CodeGen'

[iritkatriel]

I'll merge this PR now, it's getting into merge conflicts all the time. We can remove these from the API later if it's possible.