Arsd:cgi server stall

[Marcelo Silva Nascimento Mancini]

I'm not able to produce a minimally reproducible example.

1: Clone https://github.com/MrcSnm/HipremeEngine
2: Run dub at tools/user/build_selector
3: Run the small setup and select the game as start_here
4: Run the webassembly build
5: Go to the folder build/wasm and run dub to start the cgi server
6: Run the build selector again, set the game as test and build webassembly
7: Reload the webpage and get a stall

[Adam D. Ruppe]

This seems to be fixed as of version tag 11.x, though I was never able to reproduce before or after.