Timedelta Comparisons Inconsistent
Motivation: fleshing out some `Tick` operations, in particular comparisons.  The natural thing to do for these is to dispatch to their `Timedelta` implementations.  But since #20829 this now fails.

We have existing tests that e.g. `Minute(1) < "foo"` raises a `TypeError`.  But since 20829 `Timedelta(minutes=1) < "foo"` only raises in PY3.

We should consider reverting 20829, or at least making it more specific to only return `NotImplemented` for _specific_ types, rather than any non-comparable type.