init: add ctl.oneshot_on/ctl.oneshot_off

Some services are lazy HALs on some platforms and not lazy HALs on
others; this is known at runtime by hwservicemanager, so this change
adds these properties to allow hwservicemanager to turn one oneshot
(for lazy HALs).  It may also be required to make a lazy HAL not lazy
anymore, and oneshot_off is provided for this.

Bug: 147841742
Test: new unit test that turn on and off oneshot on a service (bootanim)
      and observes that it follows the expected behavior
Change-Id: I79524e2c9a5008f90c8d3bc40920fde00602a439
diff --git a/init/Android.bp b/init/Android.bp
index 72a7bfe..d2bdf98 100644
--- a/init/Android.bp
+++ b/init/Android.bp
@@ -240,6 +240,7 @@
         "firmware_handler_test.cpp",
         "init_test.cpp",
         "keychords_test.cpp",
+        "oneshot_on_test.cpp",
         "persistent_properties_test.cpp",
         "property_service_test.cpp",
         "property_type_test.cpp",