BUG: pd.Timestamp loses fold when removing timezone which is inconsistent with datetime.datetime
- [+] I have checked that this issue has not already been reported.

- [+] I have confirmed this bug exists on the latest version of pandas.
I have tested on {'dirty': False, 'error': None, 'full-revisionid': '67a3d4241ab84419856b84fc3ebc9abcbe66c6b3', 'version': '1.1.4'}

- [-] (optional) I have confirmed this bug exists on the master branch of pandas.

---

**Note**: Please read [this guide](https://matthewrocklin.com/blog/work/2018/02/28/minimal-bug-reports) detailing how to provide the necessary information for us to reproduce your bug.

#### Problem description

datetime.datetime saves the fold when replacing tzinfo, but pandas.Timestamp doesn't 

#### Code Sample, a copy-pastable example

```python
import dateutil.tz
import pandas
from datetime import datetime as dt
print(pandas.Timestamp(1256427000000000000, tz=dateutil.tz.gettz('Europe/Moscow'), unit='ns'))
# Timestamp('2009-10-25 02:30:00+0300', tz='dateutil//usr/share/zoneinfo/Europe/Moscow')
print(pandas.Timestamp(1256427000000000000, tz=dateutil.tz.gettz('Europe/Moscow'), unit='ns').fold)
# 1
print(pandas.Timestamp(1256427000000000000, tz=dateutil.tz.gettz('Europe/Moscow'), unit='ns').replace(tzinfo=None).fold)
# 0
print(dt(2009, 10, 25, 2,30, fold=1, tzinfo=dateutil.tz.gettz('Europe/Moscow')).replace(tzinfo=None).fold)
# 1
```


#### Expected Output
```
Timestamp('2009-10-25 02:30:00+0300', tz='dateutil//usr/share/zoneinfo/Europe/Moscow')
1
1
1
```

#### Output of ``pd.show_versions()``

<details>


commit           : 67a3d4241ab84419856b84fc3ebc9abcbe66c6b3
python           : 3.8.4.final.0
python-bits      : 64
OS               : Darwin
OS-release       : 19.5.0
Version          : Darwin Kernel Version 19.5.0: Tue May 26 20:41:44 PDT 2020; root:xnu-6153.121.2~2/RELEASE_X86_64
machine          : x86_64
processor        : i386
byteorder        : little
LC_ALL           : None
LANG             : en_US.UTF-8
LOCALE           : en_US.UTF-8

pandas           : 1.1.4
numpy            : 1.16.4
pytz             : 2020.4
dateutil         : 2.8.0
pip              : 20.1.1
setuptools       : 39.0.1
Cython           : 3.0a6
pytest           : 5.0.1
hypothesis       : None
sphinx           : None
blosc            : None
feather          : None
xlsxwriter       : None
lxml.etree       : None
html5lib         : None
pymysql          : None
psycopg2         : 2.8.3 (dt dec pq3 ext lo64)
jinja2           : 2.10.1
IPython          : None
pandas_datareader: None
bs4              : None
bottleneck       : None
fsspec           : None
fastparquet      : None
gcsfs            : None
matplotlib       : 3.0.3
numexpr          : None
odfpy            : None
openpyxl         : 3.0.5
pandas_gbq       : None
pyarrow          : None
pytables         : None
pyxlsb           : None
s3fs             : None
scipy            : None
sqlalchemy       : None
tables           : None
tabulate         : 0.8.6
xarray           : None
xlrd             : 1.2.0
xlwt             : None
numba            : None

</details>
