fixup! wait for ready only if there is backpressure

Author: MattiasBuelens

lib/internal/webstreams/readablestream.js

@@ -1532,10 +1532,12 @@ function readableStreamPipeTo(
   }
 
   async function step() {
-    if (shuttingDown)
-      return true;
+    if (shuttingDown) return true;
 
-    await writer[kState].ready.promise;
+    if (dest[kState].backpressure) {
+      await writer[kState].ready.promise;
+      if (shuttingDown) return true;
+    }
 
     const controller = source[kState].controller;