Added OLT adapter restart test

Adds a test to restart the open olt adapter after the
ONU is authenticated and then completes to ONU DHCP
after the adapter is restarted.

Updates the core restart test to only loop over ONUs
for ONU specific steps as opposed to restart the core
for each ONU.

Addresses a bug in the voltha.robot library to ensure
the port forward process is seen by ps.

Change-Id: Ief16c9b6127267ea58fe4f4690b2c2868ad28664
diff --git a/Makefile b/Makefile
index eb72d07..45ec35f 100644
--- a/Makefile
+++ b/Makefile
@@ -62,6 +62,11 @@
 rwcore-restart-single-kind: ROBOT_FILE := Voltha_PODTests.robot
 rwcore-restart-single-kind: voltha-test
 
+single-kind: ROBOT_MISC_ARGS += -X -i $(TEST_TAGS) $(ROBOT_DEBUG_LOG_OPT)
+single-kind: ROBOT_CONFIG_FILE := $(ROBOT_SANITY_SINGLE_PON_FILE)
+single-kind: ROBOT_FILE := Voltha_PODTests.robot
+single-kind: voltha-test
+
 sanity-multi-kind: ROBOT_MISC_ARGS += -i sanity $(ROBOT_DEBUG_LOG_OPT)
 sanity-multi-kind: ROBOT_CONFIG_FILE := $(ROBOT_SANITY_MULT_PON_FILE)
 sanity-multi-kind: bbsim-kind