sort_values inplace=True clears dataframe contents

[gshimansky]

System information

• OS Platform and Distribution (e.g., Linux Ubuntu 16.04):

Ubuntu 20.04

• Modin version (modin.__version__):

0.7.4+28.g7c94902

• Python version:

Python 3.8.2

• Code we can use to reproduce:

import modin.pandas as pd

df = pd.DataFrame({"col": [2, 51, 17],}, index=["abc", "def", "ghi"])
print(df)
print(df.index)
df.sort_values(by=["col"], inplace=True)
print(df)

Describe the problem

This code when ran on Modin produces a dataframe with NaN contents instead of sorted values.

Source code / logs

[gshimansky]

Fixed as a part of #1754