test_dti_tz_localize_roundtrip fails locally
#### Code Sample, a copy-pastable example if possible

```python
pandas.test(['-k', 'test_dti_tz_localize_roundtrip'])

pandas/tests/indexes/datetimes/test_timezones.py ...........................F............                                                                     [100%]

============================================================================= FAILURES ==============================================================================
_________________________________________ TestDatetimeIndexTimezones.test_dti_tz_localize_roundtrip[tz_aware_fixture6-idx3] _________________________________________

self = <pandas.tests.indexes.datetimes.test_timezones.TestDatetimeIndexTimezones object at 0x1c27c88f28>, tz_aware_fixture = tzlocal()
idx = DatetimeIndex(['2014-08-01 00:00:00', '2014-08-01 00:01:00',
               '2014-08-01 00:02:00', '2014-08-01 00:03:0...          '2014-10-30 23:59:00', '2014-10-31 00:00:00'],
              dtype='datetime64[ns]', length=131041, freq='T')

    @pytest.mark.parametrize('idx', [
        date_range(start='2014-01-01', end='2014-12-31', freq='M'),
        date_range(start='2014-01-01', end='2014-12-31', freq='D'),
        date_range(start='2014-01-01', end='2014-03-01', freq='H'),
        date_range(start='2014-08-01', end='2014-10-31', freq='T')
    ])
    def test_dti_tz_localize_roundtrip(self, tz_aware_fixture, idx):
        tz = tz_aware_fixture
        localized = idx.tz_localize(tz)
        expected = date_range(start=idx[0], end=idx[-1], freq=idx.freq,
                              tz=tz)
>       tm.assert_index_equal(localized, expected)
E       AssertionError: Index are different
E       
E       Index length are different
E       [left]:  131041, DatetimeIndex(['2014-08-01 00:00:00+01:00', '2014-08-01 00:01:00+01:00',
E                      '2014-08-01 00:02:00+01:00', '2014-08-01 00:03:00+01:00',
E                      '2014-08-01 00:04:00+01:00', '2014-08-01 00:05:00+01:00',
E                      '2014-08-01 00:06:00+01:00', '2014-08-01 00:07:00+01:00',
E                      '2014-08-01 00:08:00+01:00', '2014-08-01 00:09:00+01:00',
E                      ...
E                      '2014-10-30 23:51:00+00:00', '2014-10-30 23:52:00+00:00',
E                      '2014-10-30 23:53:00+00:00', '2014-10-30 23:54:00+00:00',
E                      '2014-10-30 23:55:00+00:00', '2014-10-30 23:56:00+00:00',
E                      '2014-10-30 23:57:00+00:00', '2014-10-30 23:58:00+00:00',
E                      '2014-10-30 23:59:00+00:00', '2014-10-31 00:00:00+00:00'],
E                     dtype='datetime64[ns, tzlocal()]', length=131041, freq='T')
E       [right]: 131101, DatetimeIndex(['2014-08-01 00:00:00+01:00', '2014-08-01 00:01:00+01:00',
E                      '2014-08-01 00:02:00+01:00', '2014-08-01 00:03:00+01:00',
E                      '2014-08-01 00:04:00+01:00', '2014-08-01 00:05:00+01:00',
E                      '2014-08-01 00:06:00+01:00', '2014-08-01 00:07:00+01:00',
E                      '2014-08-01 00:08:00+01:00', '2014-08-01 00:09:00+01:00',
E                      ...
E                      '2014-10-30 23:51:00+00:00', '2014-10-30 23:52:00+00:00',
E                      '2014-10-30 23:53:00+00:00', '2014-10-30 23:54:00+00:00',
E                      '2014-10-30 23:55:00+00:00', '2014-10-30 23:56:00+00:00',
E                      '2014-10-30 23:57:00+00:00', '2014-10-30 23:58:00+00:00',
E                      '2014-10-30 23:59:00+00:00', '2014-10-31 00:00:00+00:00'],
E                     dtype='datetime64[ns, tzlocal()]', length=131101, freq='T')

pandas/tests/indexes/datetimes/test_timezones.py:448: AssertionError
```
#### Problem description

Fails locally but passes in CI on the same commit. Its because the test fixture includes `tzlocal()`, and for some timezones (incl most of europe), one of the testcases spans a DST transition:

`date_range(start='2014-08-01', end='2014-10-31', freq='T')`

#### Expected Output

should pass, regardless of the local timezone

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

<details>

INSTALLED VERSIONS
------------------
commit: 7c842b0312064bbc6bf1201ba6dbb774da90ba0d
python: 3.7.2.final.0
python-bits: 64
OS: Darwin
OS-release: 18.2.0
machine: x86_64
processor: i386
byteorder: little
LC_ALL: None
LANG: en_GB.UTF-8
LOCALE: en_GB.UTF-8

pandas: 0.24.0.dev0+1539.g7c842b031
pytest: 4.0.2
pip: 18.1
setuptools: 40.6.2
Cython: 0.29.2
numpy: 1.15.4
scipy: 1.1.0
pyarrow: None
xarray: None
IPython: 7.2.0
sphinx: 1.8.2
patsy: 0.5.1
dateutil: 2.7.5
pytz: 2018.7
blosc: None
bottleneck: 1.2.1
tables: 3.4.4
numexpr: 2.6.8
feather: None
matplotlib: 3.0.2
openpyxl: 2.5.12
xlrd: 1.2.0
xlwt: 1.3.0
xlsxwriter: 1.1.2
lxml.etree: 4.2.5
bs4: 4.6.3
html5lib: 1.0.1
sqlalchemy: 1.2.15
pymysql: 0.9.2
psycopg2: None
jinja2: 2.10
s3fs: 0.2.0
fastparquet: None
pandas_gbq: None
pandas_datareader: None
gcsfs: 0.2.0
>>>
</details>
