fix: Prevent shimming objects as a function even when objects start with on

[gvking]

The blink wpt tests are failing when EME logger is enabled due to shimming anything starting with on as a function.
This is fixed by using the js property of object.hasOwnProperty, which only looks at the properties of the object, not the ones that are inherited.

[joeyparrish]

Discussed with John, and we think the WPT test is at fault. The test checks that all the properties of an object have the "right" types, but it never sets the "on" handlers at all. When a property is null, typeof returns object, so the test expects that they "on" handlers are all objects.

Since the values for those aren't set in the test, it makes no sense to set expectations on their types. They should either be set to functions and checked for function type, or not set and not checked.