Separate system_ext_property_contexts out of system sepolicy.

Bug: 137712473
Test: boot crosshatch
Change-Id: I27db30edfd9948675793fdfec19081288f8017eb
diff --git a/Android.mk b/Android.mk
index 5cb79be..e570247 100644
--- a/Android.mk
+++ b/Android.mk
@@ -318,6 +318,8 @@
     system_ext_file_contexts_test \
     system_ext_hwservice_contexts \
     system_ext_hwservice_contexts_test \
+    system_ext_property_contexts \
+    system_ext_property_contexts_test \
     system_ext_seapp_contexts \
     system_ext_mapping_file \