feat: add test for .wasm files

[WofWca]

A potential gotcha is MIME type. See
deltachat/deltachat-android#2635

Closes #20

[WofWca]

Currently the test succeeds on Desktop and fails on Android.

[r10s]

not sure if the test outcome is correct:

• it says "WASM not supported" on deltachat-ios (which may be true) ...
• it also says "WASM not supported" when opened in the safari-browser on mac - where things as https://eugenyn.itch.io/amazing-track or https://stackoverflow.com/questions/47879864/how-can-i-check-if-a-browser-supports-webassembly report that wasm works in the same browser

did not test android

EDIT: looking at the code, might be that the path for fetch() is not working in the browser; needs more investigation

[WofWca]

it says "WASM not supported" on deltachat-ios (which may be true) ...

I don't know, I haven't looked at the source code there. Maybe it's the same as deltachat/deltachat-android#2635

it also says "WASM not supported" when opened in the safari-browser on mac

Again, how did you test it? By opening it as file:// or by setting up an http server? I'm not sure if fetch() is supposed to work like this for file: URLs.