Allow WTF timers to participate in the event loop

[190n]

What does this PR do?

WebKit has WTF::RunLoop and WTF::RunLoop::Timer. The latter is created in order to run GC at certain intervals. Since Bun's event loop is really in charge of timers, rather than the RunLoop, the GC timers would previously never run. This PR enables Bun to include those timers in the event loop and fire them at the right times.

This also includes the change from #14885 to release heap access while waiting for events.

TODO:

• fix todos in the code
• performance testing
• make the test suite reasonable (probably just check Process freezed after upgrade from 1.1.33 to 1.1.34 #14982 does not regress)
• see if we can get rid of GarbageCollectionController from event_loop.zig

Requires oven-sh/WebKit#71 and #15328

How did you verify your code works?

TODO

[robobun]

^{Updated 11:14 AM PT - Dec 22nd, 2024}

❌ @Jarred-Sumner, your commit eea51d9 has some failures in #8425

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🧪   try this PR locally:

bunx bun-pr 15557