gpu-compute,tests: Move GPU tests to testlib (#1270)

A new host tag `gcn_gpu` has been added. This allows for selection of
those GPU tests which depend upon the gcn-gpu docker image to run.

In addition to this, the square GPU tests has been moved to the CI
tests. This ensures some GPU code is compiled and run on every PR.

configs/example/apu_se.py

@@ -40,6 +40,7 @@ from m5.objects import *
 from m5.util import addToPath
 
 from gem5.isas import ISA
+from gem5.resources.resource import obtain_resource
 from gem5.runtime import get_supported_isas
 
 addToPath("../")
@@ -402,6 +403,22 @@ parser.add_argument(
     help="cache replacement policy" "policy for sqc",
 )
 
+parser.add_argument(
+    "--download-resource",
+    type=str,
+    default=None,
+    required=False,
+    help="Download this resources prior to simulation",
+)
+
+parser.add_argument(
+    "--download-dir",
+    type=str,
+    default=None,
+    required=False,
+    help="Download resources to this directory",
+)
+
 Ruby.define_options(parser)
 
 # add TLB options to the parser
@@ -409,6 +426,17 @@ GPUTLBOptions.tlb_options(parser)
 
 args = parser.parse_args()
 
+# Get the resource if specified.
+if args.download_resource:
+    resources = obtain_resource(
+        resource_id=args.download_resource,
+        resource_directory=args.download_dir,
+    )
+
+    # This line seems pointless but is actually what triggers the download.
+    resources.get_local_path()
+
+
 # The GPU cache coherence protocols only work with the backing store
 args.access_backing_store = True