[JSG] Explicitly set template parameter in returnRejectedPromise()

The compiler would drop the reference otherwise, resulting in the info parameter
being copyied implicitly. This caused //src/workerd/io:promise-wrapper-test to
fail.

src/workerd/jsg/util.c++

@@ -614,14 +614,14 @@ void returnRejectedPromise(
     const v8::FunctionCallbackInfo<v8::Value>& info,
     v8::Local<v8::Value> exception,
     v8::TryCatch& tryCatch) {
-  return returnRejectedPromiseImpl(info, exception, tryCatch);
+  return returnRejectedPromiseImpl<const v8::FunctionCallbackInfo<v8::Value>&>(info, exception, tryCatch);
 }
 
 void returnRejectedPromise(
     const v8::PropertyCallbackInfo<v8::Value>& info,
     v8::Local<v8::Value> exception,
     v8::TryCatch& tryCatch) {
-  return returnRejectedPromiseImpl(info, exception, tryCatch);
+  return returnRejectedPromiseImpl<const v8::PropertyCallbackInfo<v8::Value>&>(info, exception, tryCatch);
 }
 
 // ======================================================================================