lib: remove unnecessary async

Co-authored-by: Jason Zhang <xzha4350@gmail.com>
PR-URL: #54829
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Michael Dawson <midawson@redhat.com>

lib/internal/webstreams/adapters.js

@@ -176,7 +176,7 @@ function newWritableStreamFromStreamWritable(streamWritable) {
   return new WritableStream({
     start(c) { controller = c; },
 
-    async write(chunk) {
+    write(chunk) {
       if (streamWritable.writableNeedDrain || !streamWritable.write(chunk)) {
         backpressurePromise = createDeferredPromise();
         return SafePromisePrototypeFinally(