Add sepolicy for build prop for go/vabc-xor

Add a new build prop for the new Vritual AB Compression with XOR
feature. This allows each lunch target to control if they want to use
the new feature.

Test: th
Bug: 177104308
Change-Id: Ibafc231daecef5e482652d1769ad0f3729206c0f
diff --git a/private/property_contexts b/private/property_contexts
index 7f97281..0761ede 100644
--- a/private/property_contexts
+++ b/private/property_contexts
@@ -285,6 +285,7 @@
 ro.virtual_ab.enabled   u:object_r:virtual_ab_prop:s0 exact bool
 ro.virtual_ab.retrofit  u:object_r:virtual_ab_prop:s0 exact bool
 ro.virtual_ab.compression.enabled  u:object_r:virtual_ab_prop:s0 exact bool
+ro.virtual_ab.compression.xor.enabled   u:object_r:virtual_ab_prop:s0 exact bool
 snapuserd.ready         u:object_r:snapuserd_prop:s0 exact bool
 snapuserd.proxy_ready   u:object_r:snapuserd_prop:s0 exact bool