BUG: Timedelta == ndarray[td64]
- [ ] closes #xxxx
- [x] tests added / passed
- [x] passes `black pandas`
- [x] passes `git diff upstream/master -u -- "*.py" | flake8 --diff`
- [x] whatsnew entry

xref #33346

Between the two of these, we should be able to get rid of this kludge: https://github.com/pandas-dev/pandas/blob/master/pandas/core/internals/managers.py#L629

IIRC there were some test_coercion xfails related to that kludge, will be worth revisiting.
> do we have tests for NaT (object and inside the ndarray and 0-dim?

no, i have the 0-d case in my notes for a follow-up thanks