BUG: to_string with index=False incorrectly shifts truncation (ellipsis) column
- [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.

---

**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.

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

```python
import pandas as pd
df = pd.DataFrame([[0]*100] * 10)
print(df.to_string(index=False, max_cols=20))
```

Output
```
 0   1   2   3   4   5   6   7   8   9   90  ...  91  92  93  94  95  96  97  98  99
  0   0   0   0   0   0   0   0   0   0   0  ...   0   0   0   0   0   0   0   0   0
  0   0   0   0   0   0   0   0   0   0   0  ...   0   0   0   0   0   0   0   0   0
  0   0   0   0   0   0   0   0   0   0   0  ...   0   0   0   0   0   0   0   0   0
  0   0   0   0   0   0   0   0   0   0   0  ...   0   0   0   0   0   0   0   0   0
  0   0   0   0   0   0   0   0   0   0   0  ...   0   0   0   0   0   0   0   0   0
  0   0   0   0   0   0   0   0   0   0   0  ...   0   0   0   0   0   0   0   0   0
  0   0   0   0   0   0   0   0   0   0   0  ...   0   0   0   0   0   0   0   0   0
  0   0   0   0   0   0   0   0   0   0   0  ...   0   0   0   0   0   0   0   0   0
  0   0   0   0   0   0   0   0   0   0   0  ...   0   0   0   0   0   0   0   0   0
  0   0   0   0   0   0   0   0   0   0   0  ...   0   0   0   0   0   0   0   0   0
```

#### Problem description

`to_string` is placing the truncation column (i.e. the column with the ellipses) one position too far to the right. This should not happen.

#### Expected Output
```
 0   1   2   3   4   5   6   7   8   9   ...  90  91  92  93  94  95  96  97  98  99
  0   0   0   0   0   0   0   0   0   0  ...   0   0   0   0   0   0   0   0   0   0
  0   0   0   0   0   0   0   0   0   0  ...   0   0   0   0   0   0   0   0   0   0
  0   0   0   0   0   0   0   0   0   0  ...   0   0   0   0   0   0   0   0   0   0
  0   0   0   0   0   0   0   0   0   0  ...   0   0   0   0   0   0   0   0   0   0
  0   0   0   0   0   0   0   0   0   0  ...   0   0   0   0   0   0   0   0   0   0
  0   0   0   0   0   0   0   0   0   0  ...   0   0   0   0   0   0   0   0   0   0
  0   0   0   0   0   0   0   0   0   0  ...   0   0   0   0   0   0   0   0   0   0
  0   0   0   0   0   0   0   0   0   0  ...   0   0   0   0   0   0   0   0   0   0
  0   0   0   0   0   0   0   0   0   0  ...   0   0   0   0   0   0   0   0   0   0
  0   0   0   0   0   0   0   0   0   0  ...   0   0   0   0   0   0   0   0   0   0
```

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

<details>

INSTALLED VERSIONS
------------------
commit           : f2c8480af2f25efdbd803218b9d87980f416563e
python           : 3.9.4.final.0
python-bits      : 64
OS               : Windows
OS-release       : 10
Version          : 10.0.19041
machine          : AMD64
processor        : Intel64 Family 6 Model 158 Stepping 9, GenuineIntel
byteorder        : little
LC_ALL           : None
LANG             : None
LOCALE           : English_United States.1252

pandas           : 1.2.3
numpy            : 1.20.2
pytz             : 2021.1
dateutil         : 2.8.1
pip              : 21.0.1
setuptools       : 54.1.2
Cython           : None
pytest           : 6.2.3
hypothesis       : None
sphinx           : None
blosc            : None
feather          : None
xlsxwriter       : None
lxml.etree       : None
html5lib         : None
pymysql          : None
psycopg2         : None
jinja2           : 2.11.3
IPython          : 7.22.0
pandas_datareader: None
bs4              : 4.9.3
bottleneck       : None
fsspec           : None
fastparquet      : None
gcsfs            : None
matplotlib       : None
numexpr          : None
odfpy            : None
openpyxl         : None
pandas_gbq       : None
pyarrow          : None
pyxlsb           : None
s3fs             : None
scipy            : None
sqlalchemy       : None
tables           : None
tabulate         : None
xarray           : None
xlrd             : None
xlwt             : None
numba            : None

</details>
