BUG: tz_localize gives incorrect shift_forward value in some European timezones
- [x] I have checked that this issue has not already been reported.

- [x] I have confirmed this bug exists on the latest version of pandas.

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

---

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

```python
In [11]: pd.to_datetime('2021-03-28 01:30').tz_localize('Europe/London', nonexistent='shift_forward')
Out[11]: Timestamp('2021-03-28 03:00:00+0100', tz='Europe/London')

In [12]: pd.to_datetime('2021-03-28 01:30').tz_localize('Europe/London', nonexistent='shift_forward') - pd.Timedelta(60, 'm')
Out[12]: Timestamp('2021-03-28 02:00:00+0100', tz='Europe/London')

In [13]: pd.to_datetime('2021-03-28 01:30').tz_localize('Europe/London', nonexistent='shift_forward') - pd.Timedelta(61, 'm')
Out[13]: Timestamp('2021-03-28 00:59:00+0000', tz='Europe/London')

```

#### Problem description

When attempting to localize a non-existent time in the Europe/London timezone using the nonexistent='shift_forward', parameter, the resulting time is 03:00 summer time-- even though the time transition skips from 01:00 AM UTC to 02:00 AM summer time.

The issue appears to occur in European timezones that are in UTC when the time is not summer time (i.e. London, Dublin, and Lisbon). Timezones that start at UTC+1 and have their summer time conversions from 2 AM-3 AM work properly.

```python
In [23]: pd.to_datetime('2021-03-28 02:30').tz_localize('Europe/Paris', nonexistent='shift_forward')
Out[23]: Timestamp('2021-03-28 03:00:00+0200', tz='Europe/Paris')

In [24]: pd.to_datetime('2021-03-28 01:30').tz_localize('Europe/Dublin', nonexistent='shift_forward')
Out[24]: Timestamp('2021-03-28 03:00:00+0100', tz='Europe/Dublin')

In [25]: pd.to_datetime('2021-03-28 01:30').tz_localize('Europe/Lisbon', nonexistent='shift_forward')
Out[25]: Timestamp('2021-03-28 03:00:00+0100', tz='Europe/Lisbon')

In [26]: pd.to_datetime('2021-03-28 02:30').tz_localize('Europe/Paris', nonexistent='shift_forward')
Out[26]: Timestamp('2021-03-28 03:00:00+0200', tz='Europe/Paris')

In [27]: pd.to_datetime('2021-03-28 02:30').tz_localize('Europe/Stockholm', nonexistent='shift_forward')
Out[27]: Timestamp('2021-03-28 03:00:00+0200', tz='Europe/Stockholm')
```



#### Expected Output

Per the documentation localizing with nonexistent='shift_forward' should "shift the nonexistent time forward to the closest existing time". In this case the closest existing time in Europe/London to 2021-03-28 01:30 would be 2021-03-28 02:00+0100.

```python
In [11]: pd.to_datetime('2021-03-28 01:30').tz_localize('Europe/London', nonexistent='shift_forward')
Out[11]: Timestamp('2021-03-28 02:00:00+0100', tz='Europe/London')
```


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

<details>

INSTALLED VERSIONS
------------------
commit           : 7d4757b4deb851bb44ab6bb20cdc404fa13fffcf
python           : 3.8.8.final.0
python-bits      : 64
OS               : Windows
OS-release       : 10
Version          : 10.0.19041
machine          : AMD64
processor        : Intel64 Family 6 Model 158 Stepping 10, GenuineIntel
byteorder        : little
LC_ALL           : None
LANG             : None
LOCALE           : English_United States.1252

pandas           : 1.3.0.dev0+1297.g7d4757b4de
numpy            : 1.20.2
pytz             : 2021.1
dateutil         : 2.8.1
pip              : 21.0.1
setuptools       : 49.6.0.post20210108
Cython           : 0.29.22
pytest           : 6.2.2
hypothesis       : 6.8.3
sphinx           : 3.5.3
blosc            : None
feather          : None
xlsxwriter       : 1.3.8
lxml.etree       : 4.6.3
html5lib         : 1.1
pymysql          : None
psycopg2         : None
jinja2           : 2.11.3
IPython          : 7.22.0
pandas_datareader: None
bs4              : 4.9.3
bottleneck       : 1.3.2
fsspec           : 0.8.7
fastparquet      : 0.5.0
gcsfs            : None
matplotlib       : 3.4.0
numexpr          : 2.7.3
odfpy            : None
openpyxl         : 3.0.7
pandas_gbq       : None
pyarrow          : 3.0.0
pyxlsb           : None
s3fs             : 0.5.2
scipy            : 1.6.2
sqlalchemy       : 1.4.3
tables           : 3.6.1
tabulate         : 0.8.9
xarray           : 0.17.0
xlrd             : 2.0.1
xlwt             : 1.3.0
numba            : 0.53.1

</details>
