tests: Fix downloader check

This test was failing due to references to a "downloader_dir" variable.
It should be "downloader_directory".

This is responsible for the Weekly test failing:
https://jenkins.gem5.org/job/weekly/55

Change-Id: Ia898726b75be1bfc2b6f49383be750a250c24af0
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/60349
Maintainer: Bobby Bruce <bbruce@ucdavis.edu>
Tested-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: Jason Lowe-Power <power.jg@gmail.com>

tests/gem5/configs/download_check.py

@@ -62,8 +62,8 @@ parser.add_argument(
 args = parser.parse_args()
 
 # If the directory doesn't exist, create it.
-if not Path(args.download_dir).exists():
-    os.makedirs(args.download_dir)
+if not Path(args.download_directory).exists():
+    os.makedirs(args.download_directory)
 
 
 ids = args.ids
@@ -83,7 +83,7 @@ for id in ids:
         continue
 
     resource_json = get_resources_json_obj(id)
-    download_path = os.path.join(args.download_dir, id)
+    download_path = os.path.join(args.download_directory, id)
     try:
         get_resource(resource_name=id, to_path=download_path)
     except Exception: