Wasm unit tests on CI

[PgBiel]

Runs wasm unit tests on CI. Browsers / exports not tested here yet.

Full details here https://typst.app/project/r314DoDea5XiYYr5bq5IFP (I will summarize them here later)

P.S. I'll be organizing commits later, sorry for the mess :)

TODO:

• [x] Add command to check.sh
• [x] Test nothreads
• [x] Ignore parallel tests in nothreads
• [ ] Ignore plugin test
• [ ] Fix godot4-prebuilt templates assuming 64-bit architecture (instead of wasm 32-bit) leading to failing struct size assertions
• [ ] Fix test_global_would_block test in global.rs when testing Wasm nothreads
• [x] Add to minimal-ci
• [ ] Add to full-ci