[dv, uvmdvgen] fixes for issue 434

- fixed base test to extend from cip_base_test if cip
- added -hi and -ha switches to indicate if interrupts / alerts are to
  be created in the testbench
- removed typedef for virtual sequencer if there are no agents (always create it)
diff --git a/util/uvmdvgen.py b/util/uvmdvgen.py
index 31c63cc..18c56f3 100755
--- a/util/uvmdvgen.py
+++ b/util/uvmdvgen.py
@@ -52,6 +52,20 @@
     )
 
     parser.add_argument(
+        "-hi",
+        "--has_interrupts",
+        default=False,
+        action='store_true',
+        help="""CIP has interrupts. Create interrupts interface in tb""")
+
+    parser.add_argument(
+        "-ha",
+        "--has_alerts",
+        default=False,
+        action='store_true',
+        help="""CIP has alerts. Create alerts interface in tb""")
+
+    parser.add_argument(
         "-ea",
         "--env_agents",
         nargs="+",
@@ -91,6 +105,8 @@
         if not args.env_agents: args.env_agents = []
         gen_env.gen_env(args.name, \
                         args.is_cip, \
+                        args.has_interrupts, \
+                        args.has_alerts, \
                         args.env_agents, \
                         args.env_outdir)