tests: Add '--skip' arg to "download_check.py"

This argument allows the passing of IDs of resources which should be
skipped for this check.

Note: A current limitation here is you cannot specify the version of a
resource. Passing the ID of a resource to this will skip the downloading
for all versions of that resource.

Change-Id: Ifdb7c2b71553126fd52a3d286897ed5dd8e98f7c

tests/gem5/gem5_resources/configs/download_check.py

@@ -52,6 +52,14 @@ parser.add_argument(
     "checked",
 )
 
+parser.add_argument(
+    "--skip",
+    nargs="+",  # Accepts 1 or more arguments.
+    type=str,
+    help="The resource IDs to skip. If not set, no resources will be skipped.",
+    required=False,
+)
+
 parser.add_argument(
     "--gem5-version",
     type=str,
@@ -86,6 +94,8 @@ if len(ids) == 0:
 errors = str()
 
 for id in ids:
+    if args.skip and id in args.skip:
+        continue
     if id not in resource_list:
         errors += (
             f"Resource with ID '{id}' not found in "