Auto merge of #25510 - pshaughn:queuemicrotask, r=jdm

Implement queueMicrotask

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The VoidFunction of a user-queued microtask is identical to a PromiseJobCallback in everything but type name, so implementing this method turned out to be just a matter of attaching a WebIDL frontend to a copy-and-pasted backend. All the remaining queueMicrotask WPT failures are because we don't have shared/service workers.

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- [X] `./mach build -d` does not report any errors
- [X] `./mach test-tidy` does not report any errors
- [X] These changes fix #21574

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- [X] There are tests for these changes

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