Adjust policy for hypervisor system properties

1. Allow them to be configured by vendor_init.
2. Introduce a new system property
   hypervisor.memory_reclaim.supported, which is configured by
   vendor_init and accessed only by virtualizationservice, and is not
   as widely accessible as the existing hypervisor sysprops.

Bug: 235579465
Test: atest MicrodroidTests
Change-Id: I952432568a6ab351b5cc155ff5eb0cb0dcddf433
diff --git a/private/property_contexts b/private/property_contexts
index b8503bd..823fa2f 100644
--- a/private/property_contexts
+++ b/private/property_contexts
@@ -640,6 +640,10 @@
 external_storage.cross_user.enabled u:object_r:storage_config_prop:s0 exact bool
 ro.fuse.bpf.enabled u:object_r:storage_config_prop:s0 exact bool
 
+# hypervisor.*: configured by the vendor to advertise capabilities of their
+# hypervisor to virtualizationservice.
+hypervisor.memory_reclaim.supported u:object_r:hypervisor_restricted_prop:s0 exact bool
+
 ro.config.per_app_memcg         u:object_r:lmkd_config_prop:s0 exact bool
 ro.lmk.critical                 u:object_r:lmkd_config_prop:s0 exact int
 ro.lmk.critical_upgrade         u:object_r:lmkd_config_prop:s0 exact bool