perf: Cache `global.Promise` for faster Promise creations

[mrousavy]

Benchmarks

10.000 calls to getValueFromJSCallbackAndWait:

const start = performance.now()
let promises: Promise<number>[] = []
for (let i = 0; i < ITERATIONS; i++) {
  promises.push(
    HybridTestObjectSwiftKotlin.getValueFromJSCallbackAndWait(() =>
      Math.random()
    )
  )
}
await Promise.all(promises)
const end = performance.now()
const nitroTime = end - start

• Before (main): ~160ms
• After (main): ~160ms

turns out this does not increase performance at all.

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1 Skipped Deployment

Project	Deployment	Preview	Comments	Updated (UTC)
nitro-docs	Skipped			Sep 9, 2025 2:06pm

[mrousavy]

@ChristopherGabba I can reproduce the error here:

- ❌ Test "JS Promise<void> can be awaited on native side" failed! Error: Expected test to not throw any errors, but an error was thrown! Error: Error: Timeouted: Promise<void> was destroyed!

[mrousavy]

nvm, it now works fine again. I broke it before, and now reverted my mistake in https://github.com/mrousavy/nitro/pull/866/commits/afab186105a3937cd548989d76818aacd66205d2.