Apply suggestion from @jasnell

Author: jasnell

src/workerd/api/node/tests/als-gc-test.js

@@ -12,7 +12,7 @@ export const test = {
         if (!storeValue) {
           throw new Error(`Failed on attempt ${i}.`);
         }
-        for (let j = 0; j < 100000; j++) {
+        for (let j = 0; j < 1_000; j++) {
           (() => Math.random())();
         }
       }

src/workerd/jsg/async-context.c++

@@ -186,5 +186,8 @@ v8::Local<v8::Object> AsyncContextFrame::getJSWrapper(Lock& js) {
   return getJSWrapper(js.v8Isolate);
 }
 
-void AsyncContextFrame::jsgVisitForGc(GcVisitor& visitor) {}
+void AsyncContextFrame::jsgVisitForGc(GcVisitor& visitor) {
+  // tracing will make the members weak and will allow
+  // them to be gc'd, which is not what we want.
+}
 }  // namespace workerd::jsg