llkd: add live-lock daemon

Introduce a standalone live-lock daemon (llkd), to catch kernel
or native user space deadlocks and take mitigating actions.

Test: llkd_unit_test
Bug: 33808187
Bug: 72838192
Change-Id: If869ecd06e5ce7b04bba1dafd0a77971b71aa517
diff --git a/private/file_contexts b/private/file_contexts
index 393993a..b55fb9d 100644
--- a/private/file_contexts
+++ b/private/file_contexts
@@ -249,6 +249,7 @@
 /system/bin/dnsmasq     u:object_r:dnsmasq_exec:s0
 /system/bin/healthd     u:object_r:healthd_exec:s0
 /system/bin/clatd	u:object_r:clatd_exec:s0
+/system/bin/llkd        u:object_r:llkd_exec:s0
 /system/bin/lmkd        u:object_r:lmkd_exec:s0
 /system/bin/usbd   u:object_r:usbd_exec:s0
 /system/bin/inputflinger u:object_r:inputflinger_exec:s0