Datetime field names use different normalization than calendar
At least under some conditions?

```python
>>> import locale
>>> import calendar
>>> import unicodedata
>>> from pandas._libs.tslibs import fields
>>> locale_name = "crh_UA.UTF-8"
>>> x = fields.get_locale_names('f_month', locale_name)[6].capitalize()
>>> y = calendar.month_name[6].capitalize()

>>> x == y
# False

unicodedata.normalize("NFD", x) == unicodedata.normalize("NFD", y)
# True
```


this manifests in failures in https://github.com/pandas-dev/pandas/pull/21814#issuecomment-412863836