async: use zig-async-io

Signed-off-by: Francis Bouvier <francis@lightpanda.io>

src/main_wpt.zig

@@ -50,6 +50,7 @@ const Out = enum {
 pub const Types = jsruntime.reflect(apiweb.Interfaces);
 pub const GlobalType = apiweb.GlobalType;
 pub const UserContext = apiweb.UserContext;
+pub const IO = @import("asyncio").Wrapper(jsruntime.Loop);
 
 // TODO For now the WPT tests run is specific to WPT.
 // It manually load js framwork libs, and run the first script w/ js content in