fix(zone.js): Promise.resolve(subPromise) should return subPromise

In the original `Promise` impelmentation, zone.js follow the spec from
https://promisesaplus.com/#point-51.

```
const p1 = Promise.resolve(1);
const p2 = Promise.resolve(p1);

p1 === p2; // false
```
in this case, `p2` should be the same status with `p1` but they are
still different instances.

And for some edge case.

```
class MyPromise extends Promise {
  constructor(sub) {
    super((res) => res(null));
    this.sub = sub;
  }
  then(onFufilled, onRejected) {
    this.sub.then(onFufilled, onRejected);
  }
}

const p1 = new Promise(setTimeout(res), 100);
const myP = new MyPromise(p1);
const r = await myP;
r === 1; // false
```

So in the above code, `myP` is not the same instance with `p1`,
and since `myP` is resolved in constructor, so `await myP` will
just pass without waiting for `p1`.

And in the current `tc39` spec here https://tc39.es/ecma262/multipage/control-abstraction-objects.html#sec-promise-resolve
`Promise.resolve(subP)` should return `subP`.

```
const p1 = Promise.resolve(1);
const p2 = Promise.resolve(p1);

p1 === p2; // true
```

So the above `MyPromise` can wait for the `p1` correctly.

.github/workflows/ci.yml

@@ -234,7 +234,6 @@ jobs:
         # Install
       - run: yarn --cwd packages/zone.js install --frozen-lockfile --non-interactive
         # Run zone.js tools tests
-      - run: yarn --cwd packages/zone.js promisetest
       - run: yarn --cwd packages/zone.js promisefinallytest
       - run: yarn --cwd packages/zone.js jest:test
       - run: yarn --cwd packages/zone.js jest:nodetest

packages/zone.js/lib/common/promise.ts

@@ -292,6 +292,9 @@ Zone.__load_patch('ZoneAwarePromise', (global: any, Zone: ZoneType, api: _ZonePr
     }
 
     static resolve<R>(value: R): Promise<R> {
+      if (value instanceof ZoneAwarePromise) {
+        return value;
+      }
       return resolvePromise(<ZoneAwarePromise<R>>new this(null as any), RESOLVED, value);
     }
 

packages/zone.js/test/common/Promise.spec.ts

@@ -6,7 +6,7 @@
  * found in the LICENSE file at https://angular.io/license
  */
 
-import {isNode, zoneSymbol} from '../../lib/common/utils';
+import {isNode} from '../../lib/common/utils';
 import {ifEnvSupports} from '../test-util';
 
 declare const global: any;
@@ -76,6 +76,12 @@ describe(
         expect(new Promise(() => null) instanceof Promise).toBe(true);
       });
 
+      it('Promise.resolve(subPromise) should equal to subPromise', () => {
+        const p1 = Promise.resolve(1);
+        const p2 = Promise.resolve(p1);
+        expect(p1).toBe(p2);
+      });
+
       xit('should ensure that Promise this is instanceof Promise', () => {
         expect(() => {
           Promise.call({} as any, () => null);
@@ -130,6 +136,19 @@ describe(
         expect(new MyPromise(() => {}).then(() => null) instanceof MyPromise).toBe(true);
       });
 
+      it('should allow subclassing with own then', (done: DoneFn) => {
+        class MyPromise extends Promise<any> {
+          constructor(private sub: Promise<any>) {
+            super((resolve) => {resolve(null)});
+          }
+        }
+        const p = Promise.resolve(1);
+        new MyPromise(p).then((v) => {
+          expect(v).toBe(1);
+          done();
+        });
+      });
+
       it('Symbol.species should return ZoneAwarePromise', () => {
         const empty = function() {};
         const promise = Promise.resolve(1);