Unified event loop

[Jarred-Sumner]

This makes it so JavaScriptCore schedules tasks to Bun's event loop, instead of Bun's event loop periodically checking if JavaScriptCore's event loop has any work to do.

This properly fixes #3524

Fixes #2353
Fixes #1189

A better fix for #127

Surprisingly, does not fix #2732 but I suspect the reproduction's WASM file is invalid

[github-actions]

❌ @Jarred-Sumner 7 files with test failures on bun-darwin-aarch64:

• test/bundler/esbuild/ts.test.ts
• test/cli/install/bun-install.test.ts
• test/js/bun/net/socket.test.ts
• test/js/bun/spawn/spawn.test.ts
• test/js/bun/test/test-test.test.ts
• test/js/node/watch/fs.watch.test.ts
• test/js/web/fetch/fetch-leak.test.js

View test output

^{#5eb0b6054d8673a1c7b3c1a925a82d86b9ddadde}

[github-actions]

❌ @Jarred-Sumner 2 files with test failures on linux-x64:

• test/bundler/esbuild/ts.test.ts
• test/js/web/fetch/fetch-leak.test.js

View test output

^{#5eb0b6054d8673a1c7b3c1a925a82d86b9ddadde}

[github-actions]

❌ @Jarred-Sumner 2 files with test failures on linux-x64-baseline:

• test/bundler/esbuild/ts.test.ts
• test/js/web/fetch/fetch-leak.test.js

View test output

^{#5eb0b6054d8673a1c7b3c1a925a82d86b9ddadde}

[github-actions]

❌ @Jarred-Sumner 6 files with test failures on bun-darwin-x64-baseline:

• test/bundler/esbuild/ts.test.ts
• test/js/bun/spawn/spawn-streaming-stdin.test.ts
• test/js/bun/sqlite/sqlite.test.js
• test/js/bun/util/sleepSync.test.ts
• test/js/third_party/webpack/webpack.test.ts
• test/js/web/timers/setTimeout.test.js

View test output

^{#5eb0b6054d8673a1c7b3c1a925a82d86b9ddadde}