util: test if `'inspect'` is in `value` before trying to read it

When using proxies or Object.defineProperty it is possible to change
the behavior of an object in a way that reading a certain property
of it is not prohibited (by throwing an error on access). It also
is possible to control the `in` keywords behavior to reflect if the
item is accessible or not. This is desireable when i.E. implementing a
whitelist for the properties of an object.

In `util.formatValue` testing with `'inspect' in value` before trying
to read `inspect.value` would help code authors to guide util. on it's
search.

Fixes #8539