bpo-35753: Fix crash in doctest with unwrap-able functions (#22981)

bpo-35753: Fix crash in doctest with unwrap-able functions (#22981)

Ignore objects that inspect.unwrap throws due to
too many wrappers.  This is a very rare case, however
it can easily be surfaced when a module under doctest
imports unitest.mock.call into its namespace.

We simply skip any object that throws this exception.
This should handle the majority of cases.