fix($rootScope, ngRepeat): accomodate objects resulting from Object.create(null)

[HandyAndyShortStack]

Use Object.hasOwnProperty.call when iterating over properties of user-supplied objects.
Allow for objects not inheriting from Object.prototype.

[lgalfaso]

If we want to support this, then the patch looks good, but every single time we change a function call to a call there is a performance implication. Given that this change is in code that is very hot, then I would like to know the opinion of other

[HandyAndyShortStack]

If we decide that using call is too expensive, we should update documentation to make it clear that users are expected to supply a hasOwnProperty property for any object watched in scopes or iterated over by ngRepeat.

[lgalfaso]

Hi @HandyAndyShortStack I think something needs to be done. The main issue is that the two places that this PR modifies are super critical, and a minor change can have a big performance change.
Once again, if objects without a prototype are going to be supported, then this looks like the right fix, I just would like other opinions

[Narretz]

@petebacondarwin landed a commit which implements this for ngRepeat (7ea2c7f), but the didn't land the change for $rootScope(which was also in #9964.
Afaik, the code in ngRepeat isn't actually that hot, as it is only used for objects. But putting it in the rootScope code is probably a bad idea.

[gkalpak]

@Narretz, I think @petebacondarwin landed it separately in 20fb626.

Closing as duplicate of #9964 (which has already been "taken care of").

[petebacondarwin]

I felt that it was worth the performance impact.