Apply suggestions from code review

Co-authored-by: Antoine du Hamel <duhamelantoine1995@gmail.com>

Author: mcollina

lib/internal/streams/duplexify.js

@@ -247,7 +247,7 @@ function fromAsyncGen(fn) {
       if (resolve !== null) {
         const _resolve = resolve;
         resolve = null;
-        _resolve({ done: true, cb() {} });
+        _resolve({ __proto__: null, done: true, cb() {} });
       }
 
       cb(err);

test/parallel/test-stream-readable-compose.js

@@ -121,13 +121,12 @@ const assert = require('assert');
   const stream = Readable.from(['hello'])
     .compose(async function *(source) {
       for await (const chunk of source) {
+        yield chunk;
         throw new Error(`boom: ${chunk}`);
       }
     })
     .compose(async function *(source) {
-      for await (const chunk of source) {
-        yield chunk;
-      }
+      yield* source;
     });
 
   assert.rejects(