feat(core): import AsyncStackTaggingZone if available

Import `AsyncStackTaggingZoneSpec` if the user imported
`zone.js/plugins/async-stack-tagging` bundle. So the user can
use `console.trace` to output the `async task` information more
clearly.

goldens/size-tracking/integration-payloads.json

@@ -2,7 +2,7 @@
   "cli-hello-world": {
     "uncompressed": {
       "runtime": 1083,
-      "main": 125325,
+      "main": 125830,
       "polyfills": 33824
     }
   },
@@ -19,14 +19,14 @@
   "cli-hello-world-ivy-compat": {
     "uncompressed": {
       "runtime": 1102,
-      "main": 132311,
+      "main": 132816,
       "polyfills": 33957
     }
   },
   "cli-hello-world-ivy-i18n": {
     "uncompressed": {
       "runtime": 926,
-      "main": 124982,
+      "main": 125487,
       "polyfills": 35252
     }
   },
@@ -55,7 +55,7 @@
   "standalone-bootstrap": {
     "uncompressed": {
       "runtime": 1090,
-      "main": 83013,
+      "main": 83515,
       "polyfills": 33945
     }
   },

packages/core/src/zone/ng_zone.ts

@@ -138,6 +138,11 @@ export class NgZone {
 
     self._outer = self._inner = Zone.current;
 
+    if ((Zone as any)['AsyncStackTaggingZoneSpec']) {
+      const AsyncStackTaggingZoneSpec = (Zone as any)['AsyncStackTaggingZoneSpec'];
+      self._inner = self._inner.fork(new AsyncStackTaggingZoneSpec('Angular'));
+    }
+
     if ((Zone as any)['TaskTrackingZoneSpec']) {
       self._inner = self._inner.fork(new ((Zone as any)['TaskTrackingZoneSpec'] as any));
     }