`Task.sleep` is not available in Embedded Swift for Wasm

[MaxDesiatov]

Description

No response

Reproduction

Install Swift SDKs for Wasm for a corresponding swift.org toolchain and try to build this code

import _Concurrency
@main struct Main {
  static func main() async {
    await Task.sleep(1234)
  }
}

It fails to build with error: 'sleep' is unavailable: unavailable in embedded Swift

Expected behavior

Code builds and works.

Environment

Apple Swift version 6.2-dev (LLVM 720e920f24c166e, Swift a5fa3edf54e72fa)
Target: arm64-apple-macosx15.0
Build config: +assertions

Additional information

No response