Bug 286885 – [JSC] `AsyncFromSyncIterator` should close its sync -iterator when `throw` is null or undefined

• Status: RESOLVED
• Resolution: FIXED
• Component: JavaScriptCore

[Sosuke Suzuki]

The normative change for `AsyncFromSyncIterator`[1] includes the following two changes:
    
    1. AsyncFromSyncIterator now closes the sync iterator when `throw` is called on the
    wrapper but is not implemented on the sync iterator. In that case, it updates the
    rejection value to a `TypeError` to reflect the contract violation.
    2. AsyncFromSyncIterator closes its sync iterator when the sync iterator yields a
    rejected promise as its value.
    
    This normative change has already been implemented in V8[2]. This patch changes to
    implement only the first change.
    
    [1]: https://github.com/tc39/ecma262/pull/2600
    [2]: https://github.com/v8/v8/commit/6c3f7aa4c76af4c3e0c89c5c279f2b98867c35f0#diff-c18e5d5743326f6ba5
44801f6ce25154b785f759885651f98924d5b56dc1c2e6

[Sosuke Suzuki]

Pull request: https://github.com/WebKit/WebKit/pull/39876

[EWS]

Committed 289726@main (72c371adc8fe): <https://commits.webkit.org/289726@main>

Reviewed commits have been landed. Closing PR #39876 and removing active labels.

[Radar WebKit Bug Importer]

<rdar://problem/144077495>