[Pal/regression] Drop unused variable in 00_Atomics.py

Pal/regression/00_Atomics.py

@@ -3,7 +3,6 @@ from regression import Regression
 
 loader = os.environ['PAL_LOADER']
 is_sgx = 'SGX_RUN' in os.environ and os.environ['SGX_RUN'] == '1'
-success = True
 
 def manifest_file(file):
     if is_sgx: