test_singularity: remove sys.argv alteration

Author: rupertnash

tests/test_singularity.py

@@ -1,7 +1,6 @@
 """Tests to find local Singularity image."""
 import shutil
 import os
-import sys
 from pathlib import Path
 
 from cwltool.main import main
@@ -14,8 +13,6 @@
     working_directory,
 )
 
-sys.argv = [""]
-
 
 @needs_singularity_2_6
 def test_singularity_pullfolder(tmp_path: Path) -> None: