[test] Add bundle fixtures

[eps1lon]

Act as a smoke test for the bundle layout.

Example run: https://app.circleci.com/pipelines/github/mui-org/material-ui/42820/workflows/210cfd58-b66f-4c3e-a3a5-4e9c00681603

TODO:

• node {12,14,16} with ES modules
• create-react-app
• nextjs + {webpack 4, webpack 5}
• gatsby
• vite
• esbuild
• snowpack
• electron? will investigate later. focusing on the web first

[mui-pr-bot]

No bundle size changes (experimental)

Generated by 🚫 dangerJS against 23aa90d

[eps1lon]

No longer pursuing manually written commonJS code. The goal is to ship only ES modules anyway so require would no longer be possible anyway. Instead we assume you always have some kind of bunlder/meta framework to consume import statements. So if you need to require you can always transpile our shipped code to commonJS modules.

[oliviertassinari]

The change looks great, but I have noticed that a growing number of PRs have been landing on HEAD unreviewed.

What do you think about asking for peer reviews and waiting for one peer review before moving forward with nontrivial changes (if no reviews move forward anyway after a reasonable amount of time)? It would help share knowledge.

[eps1lon]

The change looks great, but I have noticed that a growing number of PRs have been landing on HEAD unreviewed.

Please refer to the last meeting where we explicitly taked about this and you even said you're doing less. Could you be honest about what changed in the last days?

[oliviertassinari]

@eps1lon Sorry, I wasn't clear. In my previous message, I was proposing that we have a peer review from another member of the team. I didn't mean coming from me :)

My aim is to not be the peer review but to only leave comments where I see potential opportunities. I hope it clarifies it and is sound.