Delete namespace in background to reduce build time (#791)

* Delete namespace in background
* TPR is no longer exists

test/tests/test_obj_create_in_diff_ns.sh

@@ -10,7 +10,7 @@ ROOT=$(dirname $0)/../..
 
 final_cleanup() {
     rm -rf testDir1 || true
-    kubectl delete ns "ns1-$id" "ns2-$id" || true
+    kubectl delete ns "ns1-$id" "ns2-$id" &
 }
 
 cleanup() {
@@ -272,4 +272,4 @@ main() {
     final_cleanup
 }
 
-main
+main