Andreas Kling 9a7f836d27 LibJS: Call IteratorClose on abrupt completion in for-of loops ...

When a for-of or for-await-of loop exits via break, return, throw,
or continue-to-outer-loop, we now correctly call IteratorClose
(or AsyncIteratorClose) to give the iterator a chance to clean
up resources.

This uses a synthetic FinallyContext that wraps the LHS assignment
and loop body, reusing the existing try/finally completion record
machinery. The ReturnToFinally boundary is placed between Break
and Continue so that continue-to-same-loop bypasses the close
(zero overhead on normal iteration) while all other abrupt exits
route through the iterator close dispatch chain.

for-in (enumerate) does not require iterator close per spec.

2026-02-12 11:37:43 +01:00

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