fix(zone.js): read Symbol.species safely

We must read `Symbol.species` safely because `this` may be anything. For instance, `this`
may be an object without a prototype (created through `Object.create(null)`); thus
`this.constructor` will be undefined. One of the use cases is SystemJS creating
prototype-less objects (modules) via `Object.create(null)`. The SystemJS creates an empty
object and copies promise properties into that object (within the `getOrCreateLoad`
function). The zone.js then checks if the resolved value has the `then` method and invokes
it with the `value` context. Otherwise, this will throw an error: `TypeError: Cannot read
properties of undefined (reading 'Symbol(Symbol.species)')`.

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

@@ -463,7 +463,15 @@ Zone.__load_patch('ZoneAwarePromise', (global: any, Zone: ZoneType, api: _ZonePr
         onFulfilled?: ((value: R) => TResult1 | PromiseLike<TResult1>)|undefined|null,
         onRejected?: ((reason: any) => TResult2 | PromiseLike<TResult2>)|undefined|
         null): Promise<TResult1|TResult2> {
-      let C = (this.constructor as any)[Symbol.species];
+      // We must read `Symbol.species` safely because `this` may be anything. For instance, `this`
+      // may be an object without a prototype (created through `Object.create(null)`); thus
+      // `this.constructor` will be undefined. One of the use cases is SystemJS creating
+      // prototype-less objects (modules) via `Object.create(null)`. The SystemJS creates an empty
+      // object and copies promise properties into that object (within the `getOrCreateLoad`
+      // function). The zone.js then checks if the resolved value has the `then` method and invokes
+      // it with the `value` context. Otherwise, this will throw an error: `TypeError: Cannot read
+      // properties of undefined (reading 'Symbol(Symbol.species)')`.
+      let C = (this.constructor as any)?.[Symbol.species];
       if (!C || typeof C !== 'function') {
         C = this.constructor || ZoneAwarePromise;
       }
@@ -483,7 +491,8 @@ Zone.__load_patch('ZoneAwarePromise', (global: any, Zone: ZoneType, api: _ZonePr
     }
 
     finally<U>(onFinally?: () => U | PromiseLike<U>): Promise<R> {
-      let C = (this.constructor as any)[Symbol.species];
+      // See comment on the call to `then` about why thee `Symbol.species` is safely accessed.
+      let C = (this.constructor as any)?.[Symbol.species];
       if (!C || typeof C !== 'function') {
         C = ZoneAwarePromise;
       }