BUG: Adding two DataFrames together with duplicate column names in one results in infinite loop
#### Code Sample, a copy-pastable example

```python
df1 = pd.DataFrame(data=[[0]], columns=['second'])
df2 = pd.DataFrame(data=[[0, 0, 0]], columns=['first', 'second', 'second'])
```

<img width="191" alt="Screen Shot 2020-07-09 at 3 15 10 PM" src="https://user-images.githubusercontent.com/7226751/87081253-01d46100-c1f7-11ea-9767-5265010c62f7.png">

Adding them together never completes (infinite loop?)

```python
df1 + df2
```

#### Problem description

When adding two DataFrame where one has duplicate column names and the other has one (or more) of the duplicated columns, the operation never completes

#### Expected Output

Expected to follow rules of automatic alignment of the index.

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

<details>

INSTALLED VERSIONS
------------------
commit           : None
python           : 3.8.3.final.0
python-bits      : 64
OS               : Darwin
OS-release       : 19.4.0
machine          : x86_64
processor        : i386
byteorder        : little
LC_ALL           : None
LANG             : en_US.UTF-8
LOCALE           : en_US.UTF-8

pandas           : 1.0.5
numpy            : 1.18.5
pytz             : 2020.1
dateutil         : 2.8.1
pip              : 20.1.1
setuptools       : 47.1.1.post20200529
Cython           : None
pytest           : 5.4.2
hypothesis       : None
sphinx           : 3.1.2
blosc            : None
feather          : None
xlsxwriter       : None
lxml.etree       : 4.5.1
html5lib         : None
pymysql          : None
psycopg2         : None
jinja2           : 2.11.2
IPython          : 7.16.1
pandas_datareader: None
bs4              : 4.9.1
bottleneck       : None
fastparquet      : None
gcsfs            : None
lxml.etree       : 4.5.1
matplotlib       : 3.2.1
numexpr          : None
odfpy            : None
openpyxl         : None
pandas_gbq       : None
pyarrow          : None
pytables         : None
pytest           : 5.4.2
pyxlsb           : None
s3fs             : None
scipy            : 1.5.0
sqlalchemy       : None
tables           : None
tabulate         : 0.8.7
xarray           : None
xlrd             : None
xlwt             : None
xlsxwriter       : None
numba            : None

</details>
