WASM CI failing

[Amanieu]

https://github.com/rust-lang/stdarch/pull/1201/checks?check_run_id=3394110547

Error: failed to run main module `/checkout/target/wasm32-wasi/release/deps/core_arch-2cffe32a3ef14652.wasm`

Caused by:
    0: failed to instantiate "/checkout/target/wasm32-wasi/release/deps/core_arch-2cffe32a3ef14652.wasm"
    1: unknown import: `env::llvm.wasm.load32.zero` has not been defined

cc @alexcrichton