fix quadratic evaluation performance of async modules

[sokra]

improve runtime code for async modules

What kind of change does this PR introduce?
bugfix

Did you add tests for your changes?
yes

Does this PR introduce a breaking change?
no

What needs to be documented once your changes are merged?
nothing

[webpack-bot]

For maintainers only:

• This needs to be documented (issue in webpack/webpack.js.org will be filed when merged)
• This needs to be backported to webpack 4 (issue will be created when merged)

[jsg2021]

Could this have introduced an edge case that does not resolve?

On 7.73.0 I have a bundle when I import it I see the default key is a pending promise, and it does not appear to resolve.

but on 5.72.1 it resolves:

[vankop]

please create small reproducible repo

[jsg2021]

please create small reproducible repo

Here you go:
https://github.com/jsg2021/webpak-hanging-bundle-example

[alecmev]

@jsg2021 Have you found the cause of this hang? I'm experiencing something similar, but having a hard time narrowing it down. I just know that the problem appeared between 5.72.1 and 5.73.0.

[jsg2021]

nope. I somehow worked around it.

[alecmev]

@jsg2021 Dang... Thanks for the quick reply!

@sokra @vankop Can you take a look at the repro above, please?

[alexander-akait]

Let's investigate #16097