No need for news item as it is covered by#117909

The stats are not obviously better.

This PR reduces misses inLOAD_ATTR specializations, but it also increases the number of deferred operations due to shadowing.

BothSTORE_ATTR_WITH_HINT andLOAD_ATTR_WITH_HINT are reduced in number considerably, being replaced bySTORE_ATTR_INSTANCE_VALUE andLOAD_ATTR_INSTANCE_VALUE.

From this, it appears that this PR does what it aims to do. It also appears that it would be worth improving our handling of shadowed attributes.

I plan to fix the shadowing issue before merging this, so that it becomes a clear improvement

Now that#123040 is fixed things look much better.

Performance shows no change apart from the "go" benchmark speeds up by 35%. The "go" benchmark creates many objects before initializing them, which is a pattern that this PR allows us to optimize.

The stats show a small increase in specialization ofLOAD_ATTR with a 95% reduction of "not in dict" specialization failure. Almost certainly most of that is from the "go" benchmark.