It's useless because Inria gitlab does not have any CI runners,
and LIPN gitlab does not big (400MB) artifacts

Probably `fflate-unzip` is inconsistent because it does not have a
`'type': 'module'` field.
Should check.

Accept `?wa` as a shorthand to `?backend=wa`.

Needed for Çoqoban #sorry :)

It's a bit slow but I was bit by that when obsolete files were there mixed with
those from a newer version.

Use jsoo debug flags like in the worker build.

Note: esbuild arch-dependent deps exist; need a relatively new version of
NPM (e.g. 9.6.x).

Work around it by setting the problematic import as external.

[build] Bump SerAPI and Coq to 8.17.1