[UnitTests] Correct parametrization of cudnn target.

Previous checks for enabled runtimes were based only on the target
kind.  CuDNN is the same target kind as "cuda", and therefore needs
special handling.

python/tvm/testing.py

@@ -388,8 +388,14 @@ def _get_targets(target_str=None):
     targets = []
     for target in target_names:
         target_kind = target.split()[0]
-        is_enabled = tvm.runtime.enabled(target_kind)
-        is_runnable = is_enabled and tvm.device(target_kind).exist
+
+        if target_kind == "cuda" and "cudnn" in tvm.target.Target(target).attrs.get("libs", []):
+            is_enabled = tvm.support.libinfo()["USE_CUDNN"].lower() in ["on", "true", "1"]
+            is_runnable = is_enabled and cudnn.exists()
+        else:
+            is_enabled = tvm.runtime.enabled(target_kind)
+            is_runnable = is_enabled and tvm.device(target_kind).exist
+
         targets.append(
             {
                 "target": target,