Summary

This PR implements cleanup function support for before() hooks in the Node.js test runner, allowing test setup code to register teardown logic that runs after all after() hooks complete.

Motivation

Currently, the test runner lacks a symmetric teardown mechanism for before() hooks. While after() hooks exist, they don't provide the same locality of setup/teardown that cleanup functions offer. This pattern is common in other testing frameworks (e.g., Vitest, Jest) and improves test maintainability by keeping related setup and teardown code together.

Fixes: #55853

Key Features

LIFO Execution: Multiple cleanup functions execute in reverse order (last registered, first executed)
Async Support: Cleanup functions can be async
Error Handling: Errors in cleanup functions don't prevent other cleanups from running
Late Registration: Supports before() hooks registered inside test bodies

Implementation Details

1. Cleanup Storage:

• Added cleanup: [] array to this.hooks object
• Cleanup functions are captured in runHook() for normal before hooks
• Cleanup functions are captured in createHook() for late-registered hooks

2. Late-Registered Hook Tracking:

• Added this.pendingBeforeHooks array to track promises from late-registered hooks
• Uses async IIFE pattern to run late-registered hooks immediately and capture cleanup
• Synchronization barrier ensures all pending hooks complete before after hooks run

3. Cleanup Execution (runCleanup() method):

• Iterates cleanup array in reverse (LIFO)
• Awaits each cleanup function
• Continues execution even if individual cleanups fail