CI: Fix wasm32 build

[kleisauke]

Bump emnapi to 1.9.1 for compatibility with Emscripten 5.0.3, see:
emscripten-core/emscripten@3051725

/cc @toyobayashi FYI.

[kleisauke]

Marking as draft due to test failures:
https://github.com/kleisauke/sharp/actions/runs/23295199738/job/67740759490#step:10:24

[kleisauke]

Only 1 test failure left after commit 99803d6:
https://github.com/kleisauke/sharp/actions/runs/23297678823/job/67749563497#step:10:2086

[toyobayashi]

fixed in emnapi 1.9.1

[lovell]

@kleisauke Thanks for investigating this and @toyobayashi thanks for the quick fix.

The remaining sharp test failure appears to relate to the new toUint8Array() method, which returns a transferable ArrayBuffer rather than a non-transferable SharedArrayBuffer.

I think the WebAssembly equivalent is the shared option passed to new WebAssembly.Memory({ shared: true }), which maybe emnapi always uses? Perhaps toUint8Array should fall back to the toBuffer behaviour when run as WebAssembly?

[kleisauke]

From a quick look, an emnapi_sync_memory() call may be missing, which could be the reason for the toUint8Array() test failure.
https://toyobayashi.github.io/emnapi-docs/reference/list.html#arraybuffer-related

I'll investigate this later, but in the meantime I'm marking this PR as ready.

[lovell]

@kleisauke I fixed the test failure via commit 3879c9a (this was also affecting Electron).