fix: add microtask runner and fix promise test (#15071)

* fix: Promise resolution and unit test

* Update to use microtask runner

* Address review

atom/common/promise_util.h

@@ -32,6 +32,8 @@ class Promise : public base::RefCounted<Promise> {
                               v8::Undefined(isolate()));
   }
 
+  // Promise resolution is a microtask
+  // We use the MicrotasksRunner to trigger the running of pending microtasks
   template <typename T>
   v8::Maybe<bool> Resolve(const T& value) {
     return GetInner()->Resolve(isolate()->GetCurrentContext(),