refactor(ext/node): rewrite node:test to bypass Deno.test() layer
Rewrites the `node:test` module implementation to register tests directly
with the Rust test infrastructure via ops instead of wrapping `Deno.test()`.
Key changes:
- Tests registered directly via `op_register_test()`, returning TestResult
- Steps use `op_register_test_step()` with proper parent/root linkage
- New NodeTestContext class with plan(), skip(), todo(), diagnostic(),
waitFor(), context-level hooks, and subtest support
- SuiteCollector for synchronous suite entry collection
- Sub-suite failures properly propagate up
- Todo/skip tests correctly report as `ignored`
- Updated test.out expectations to match new behavior
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
