BUG: pytz.AmbiguousTimeError not caught in hypothesis test test_on_offset_implementations (GH41906)
- [x] closes #41906
- [x] tests added / passed
- [x] Ensure all linting tests pass, see [here](https://pandas.pydata.org/pandas-docs/dev/development/contributing.html#code-standards) for how to run them
- [ ] whatsnew entry: let me know if needed

is it possible to add the offending test case? > is it possible to add the offending test case?

Sure, any preference between 1) a separate test with `assertRaises` and 2) just an `@example(dt, offset)` to make sure the case is always tested?  prefer 1 @jreback @mroeschke 

I took at a quick look at the failing `Africa/Kinshasa` test case (also the original offending test case) under `actions-37-minimum_versions.yaml`. As expected, `pytz=2017.3` does not yet contain the DST information for `Africa/Kinshasa` that triggers `AmbiguoutTimeError` - namely `datetime.datetime(1905, 6, 30, 23, 46, 25),`. 

`python=3.8 pytz=2020.1`:
```
In[6]: import pytz
In[7]: pytz.__version__
Out[7]: '2021.1'
In[8]: pytz.timezone('Africa/Kinshasa')._utc_transition_times
Out[8]: 
[datetime.datetime(1, 1, 1, 0, 0),
 datetime.datetime(1905, 6, 30, 23, 46, 25),      # ----> triggering transition time
 datetime.datetime(1908, 7, 1, 0, 0),
 datetime.datetime(1913, 12, 31, 23, 46, 25),
 datetime.datetime(1919, 8, 31, 23, 30)]
```
`python=3.7 pytz=2017.3`:
```
>>> import pytz
>>> pytz.__version__
'2017.3'
>>> pytz.timezone('Africa/Kinshasa')._utc_transition_times
[datetime.datetime(1, 1, 1, 0, 0), datetime.datetime(1919, 8, 31, 23, 46, 24)]
```
Are you okay with removing this original offending test case in `test_nontick_offset_with_ambiguous_time_error`? 

 @jackzyliu yeah go ahead and skip for py37 (going to merge this to 1.4 which is going to have 3.7 removed anyhow), so just xfail for rn. @jreback Got it! Just updated it accordingly and rebased after master.  thanks @jackzyliu 