tests: Refactor downloading of pannotia tests (#1653)

With this patch the pannotia tests now:

1. Download the resources to 'gpu-pannotia' in the
'tests/gem5/resources' directory. This is where other test resources are
store.
2. Download thr USA-road-d.NY.gr dataset from Google cloud bucket in a
decompressed state.
2. Avoid re-download the resources if they are already present on the
host machine.

tests/gem5/gpu/test_gpu_pannotia.py

@@ -27,11 +27,14 @@
 import gzip
 import os.path
 import shutil
+from pathlib import Path
 from urllib.request import urlretrieve
 
 from testlib import *
 
-resource_path = joinpath(absdirpath(__file__), "..", "gpu-pannotia-resources")
+resource_path = joinpath(
+    absdirpath(__file__), "..", "resources", "gpu-pannotia"
+)
 binary_path = joinpath(resource_path, "pannotia-bins")
 dataset_path = joinpath(resource_path, "pannotia-datasets")
 
@@ -57,7 +60,7 @@ dataset_links = {
     "G3_circuit.graph": "https://storage.googleapis.com/dist.gem5.org/dist/develop/datasets/pannotia/mis/G3_circuit.graph",
     "ecology1.graph": "https://storage.googleapis.com/dist.gem5.org/dist/develop/datasets/pannotia/mis/ecology1.graph",
     "coAuthorsDBLP.graph": "https://storage.googleapis.com/dist.gem5.org/dist/develop/datasets/pannotia/pagerank/coAuthorsDBLP.graph",
-    "USA-road-d.NY.gr.gz": "http://www.diag.uniroma1.it/challenge9/data/USA-road-d/USA-road-d.NY.gr.gz",
+    "USA-road-d.NY.gr": "https://storage.googleapis.com/dist.gem5.org/dist/develop/datasets/pannotia/USA-road-d/USA-road-d.NY.gr",
 }
 
 
@@ -66,15 +69,14 @@ if not os.path.isdir(resource_path):
     os.makedirs(dataset_path)
 
     for name in binary_links.keys():
+        if Path(f"{binary_path}/{name}").exists():
+            continue
         urlretrieve(binary_links[name], f"{binary_path}/{name}")
     for name in dataset_links.keys():
+        if Path(f"{dataset_path}/{name}").exists():
+            continue
         urlretrieve(dataset_links[name], f"{dataset_path}/{name}")
 
-    with gzip.open(f"{dataset_path}/USA-road-d.NY.gr.gz", "rb") as f_in:
-        with open(f"{dataset_path}/USA-road-d.NY.gr", "wb") as f_out:
-            shutil.copyfileobj(f_in, f_out)
-    os.remove(f"{dataset_path}/USA-road-d.NY.gr.gz")
-
 if len(os.listdir(binary_path)) < len(binary_links):
     testlib.log.test_log.warn(
         "One or more binaries for the Pannotia GPU tests are missing! Try deleting gpu-pannotia-resources and rerunning."