Describe the bug

The display name of MSTest DataRow elements doesn't display well nulls.

Steps To Reproduce

[DataRow("", "", false)]
[DataRow(null, null, false)]
public void M1(string s1, string s2, bool b)
{
}

Expected behavior

Should be displayed as

M1 ("","",false)
M1 (null,null,false)

Actual behavior

Will be displayed as

M1 (,,false)
M1 (,,false)

Additional context

The empty string should also probably be improved to display "" instead of empty.