Allow control of AVF experiments

Grant system_server and flags_health_check permission to set the
properties that correspond to the AVF experiments.

Bug: 192819132
Test: m
Change-Id: I0e6fa73187abb4412d07ecfd42c1074b8afa5346
diff --git a/private/system_server.te b/private/system_server.te
index 4c87b3f..d06db41 100644
--- a/private/system_server.te
+++ b/private/system_server.te
@@ -712,6 +712,7 @@
 set_prop(system_server, device_config_configuration_prop)
 set_prop(system_server, device_config_connectivity_prop)
 set_prop(system_server, device_config_surface_flinger_native_boot_prop)
+set_prop(system_server, device_config_virtualization_framework_native_prop)
 
 # Allow query ART device config properties
 get_prop(system_server, device_config_runtime_native_boot_prop)