Fix top-level await parsing (#38483)

[lissein]

The previous implementation wasn't able to handle case like await (async () => {}) outside of "async" functions.

One problem is that the syntax can be exactly the same for two usecases:

Use case 1

await (async () => {})()

An await expression on the self-calling async function

Use case 2

function await(fn) {
  return () => {};
}
await (async () => {})(); // equivalent to: await((async () => {})())

A call to the function returned by a call to the "await" user defined function with the async () => {} argument.

---

We have no way to know which case we want to handle. This pull request handles Use case 2 first. If there is some identifier named "await" defined, we make this statement a function call, otherwise, we make it an await expression.

I can update this PR if someone has a better idea to handle this ambiguous case.

Fixes #38483

[lissein]

Wrong repository