Revert "Temporarily disable init_kill_services_test."

This reverts commit bd68757d4468485b5eeca561a630a31599149b9a.

Reason for revert: reland test

The test now reboots after it is completed, in case there is some state it doesn't catch locally, and servicemanager restarts more of the system.

Change-Id: I1d6d021f75ef091aa7d6973b80ed162253514697
Fixes: 156380383
Test: atest init_kill_services_test # several times on cf, check logs to confirm system finishes in clean rebooted state
diff --git a/TEST_MAPPING b/TEST_MAPPING
index 7933629..1abeb2e 100644
--- a/TEST_MAPPING
+++ b/TEST_MAPPING
@@ -28,6 +28,9 @@
       "name": "fs_mgr_vendor_overlay_test"
     },
     {
+      "name": "init_kill_services_test"
+    },
+    {
       "name": "libpackagelistparser_test"
     },
     {