suspend_blocker: Use Cuttlefish's workaround to avoid suspending the device

Reuse Cuttlefish's suspend blocker service to avoid
suspending the device while running CTS tests.

This is actuallly a cherry-pick of Amit's change on db845c here:
https://android-review.googlesource.com/c/device/linaro/dragonboard/+/1723130

The problem is that "adb shell stop" is causing a PM suspend and
subsequent loss of adb connectivity. The problem could also be reproduced by
the vts ltp test.

Test: booted to homescreen with hikey and hikey960 board,
      and adb shell stop does not cause suspend any more

Signed-off-by: Yongqin Liu <yongqin.liu@linaro.org>
Change-Id: I290faa5182135a619c4053d12a88a2d534641d7f
diff --git a/sepolicy/suspend_blocker.te b/sepolicy/suspend_blocker.te
new file mode 100644
index 0000000..fa6e02a
--- /dev/null
+++ b/sepolicy/suspend_blocker.te
@@ -0,0 +1,6 @@
+type suspend_blocker, domain;
+type suspend_blocker_exec, exec_type, vendor_file_type, file_type;
+
+init_daemon_domain(suspend_blocker);
+
+wakelock_use(suspend_blocker);