George Kalpakas a07de82f79 refactor(upgrade): avoid using static inherited method (#31986)
Using `ParentInjectorPromise.all()` (which is a static method inherited
from `SyncPromise`) causes Closure Compiler (or some related tool) to
complain:

```
TypeError: ...$packages$upgrade$src$common$src$downgrade_component_ParentInjectorPromise.all is not a function
```

Switching to `SyncPromise.all()` (the static method on the parent class)
to avoid this error.

PR Close #31986
2019-08-05 10:01:33 -07:00
..