Summary

node:test's mock.timers supports an AbortSignal.timeout API: when enabled, AbortSignal.timeout(delay) returns a signal that aborts based on the mocked virtual clock rather than real time. #33946 implemented mock.timers but intentionally shipped a subset of Node's supported APIs and left AbortSignal.timeout out, so mock.timers.enable({ apis: ['AbortSignal.timeout'] }) threw ERR_INVALID_ARG_VALUE.

This adds AbortSignal.timeout to the supported set:

• It is added to SUPPORTED_APIS.
• While enabled, globalThis.AbortSignal.timeout is replaced with a function that schedules a virtual timer (via the same internal clock as the other mocked timers) and aborts the returned signal with a TimeoutError once tick() / runAll() advance past delay.
• Because the static method is not a globalThis binding, the original is saved/restored separately from the other mocked globals, and reset() (and [Symbol.dispose]) put it back.

Tests

Enables two upstream Node conformance tests that now pass:

• parallel/test-mock-timers-abortsignal-timeout.js (passes with this change)
• parallel/test-runner-mock-timers-with-timeout.js (already passing; was simply not enabled)

and extends the node_test_mock_timers spec test with an AbortSignal.timeout case (31 → 32).

$ deno test tests/specs/node/node_test_mock_timers/test.js
ok | 32 passed | 0 failed

$ cargo test --test node_compat -- test-mock-timers-abortsignal-timeout
test node_compat::parallel::test-mock-timers-abortsignal-timeout.js ... ok

$ cargo test --test node_compat -- test-runner-mock-timers-with-timeout
test node_compat::parallel::test-runner-mock-timers-with-timeout.js ... ok

Towards #32987 / #35414.

Note: the remaining upstream mock-timers conformance files (-date.js, -scheduler.js, and the main test-runner-mock-timers.js) are intentionally left out. The first two rely on Node's automatic per-test mock restore (Deno's node:test has no per-test mock tracker yet) and scheduler.wait, and the main file requires --expose-internals / internal/timers. Those are separate follow-ups.