[wasm-web-api-2] Align with Web IDL specification

[autokagami]

🤖 This is an automated pull request to align the spec with the latest Web IDL specification. 🤖

The followings are the Web IDL validation messages, which may help understanding this PR:

• Validation error at line 3 in wasm-web-api-2,0, inside `namespace WebAssembly -> operation compileStreaming -> argument options`:
  > source, optional WebAssemblyCompileOptions options);
                                               ^
  

  Error: Optional dictionary arguments must have a default value of {}.

• Validation error at line 5 in wasm-web-api-2,0, inside `namespace WebAssembly -> operation instantiateStreaming -> argument options`:
   object importObject, optional WebAssemblyCompileOptions options);
                                                           ^
  

  Error: Optional dictionary arguments must have a default value of {}.

Currently this autofix might introduce awkward code formatting, and feel free to manually fix it whenever it happens.

Please file an issue at https://github.com/saschanaz/webidl-updater/issues/new if you think this is invalid or should be enhanced.