http: remove unnecessary await in listenAndServe()

Original: https://github.com/denoland/deno_std/commit/d1971241d90bdb7fcb612e2d922ed99a0419e2f4

http/server.ts

@@ -312,7 +312,7 @@ export async function listenAndServe(
   const server = serve(addr);
 
   for await (const request of server) {
-    await handler(request);
+    handler(request);
   }
 }