Eliminate redundant refcounting in the JIT for `BINARY_OP_EXTEND`

[aisk]

Feature or enhancement

Proposal:

As a follow-up to #134584, we can eliminate redundant ref-counting for BINARY_OP_EXTEND.

Has this already been discussed elsewhere?

I have already discussed this feature proposal on Discourse

Links to previous discussion of this feature:

#143995 (comment)

Linked PRs

• gh-144005: Eliminate redundant refcounting in the JIT for BINARY_OP_EXTEND #144006