[3.11] GH-93516: Backport GH-93769: Store offset of first traceable instruction in code object

[markshannon]

No description provided.

[markshannon]

The ABI check fails, due to adding the _co_firsttraceable field.
I've added it near the end, so that code that accesses fields other that co_extra and co_code_adaptive will not be effected.

[nedbat]

I tried this compared to 3.11.0b3, and this code is slightly slower?

cov	proj	python3.11	gh93818	93818 vs 3.11
6.4.1	bug1339.py	0.846 s	0.856 s	101.20%
6.4.1	bm_sudoku.py	55.436 s	57.561 s	103.83%
6.4.1	bm_spectral_norm.py	66.488 s	68.803 s	103.48%

[markshannon]

Odd.
I wouldn't expect this to have much effect compared to removing the overhead of line number lookup, or caching the result of PyCode_GetCode(), but I would expect it to be positive.

Let's remeasure after those are merged.

[pablogsal]

I'm regenerating the ABI in this PR

[pablogsal]

@markshannon I cannot push to the remote repo, could you please ensure the "allow pushes from maintainers checkbox is activated on the right column"?

[markshannon]

Closing this until I've had time to investigate the slowdown once #94127 is merged.