lib,test: enable wasm/webapi/empty-body WPT

Refs: #42701
Refs: nodejs/undici#1346
Refs: #42939

PR-URL: #42960
Reviewed-By: Antoine du Hamel <duhamelantoine1995@gmail.com>
Reviewed-By: Joyee Cheung <joyeec9h3@gmail.com>

Author: tniessen

lib/internal/bootstrap/pre_execution.js

@@ -250,8 +250,11 @@ function setupFetch() {
       }
 
       // Pass all data from the response body to the WebAssembly compiler.
-      for await (const chunk of response.body) {
-        streamState.push(chunk);
+      const { body } = response;
+      if (body != null) {
+        for await (const chunk of body) {
+          streamState.push(chunk);
+        }
       }
     })().then(() => {
       // No error occurred. Tell the implementation that the stream has ended.

test/wpt/status/wasm/webapi.json

@@ -12,9 +12,6 @@
   "contenttype.any.js": {
     "skip": "WPTRunner does not support fetch()"
   },
-  "empty-body.any.js": {
-    "skip": "Bug in undici, see https://github.com/nodejs/undici/issues/1345"
-  },
   "idlharness.any.js": {
     "skip": "not configured"
   },