Use prebuilts for compat test if prebuilts exist

system/sepolicy should support both REL build and ToT build. That means
that system/sepolicy and prebuilts may differ. As the frozen sepolicy is
what vendor sepolicy uses, so we need to use prebuilts to run Treble
compat test.

Bug: 296875906
Test: m selinux_policy on REL
Change-Id: I4b290266ba87e3f011d640bec133fc88359ea52f
diff --git a/prebuilts/api/32.0/Android.bp b/prebuilts/api/32.0/Android.bp
index f1fb581b..39722b4 100644
--- a/prebuilts/api/32.0/Android.bp
+++ b/prebuilts/api/32.0/Android.bp
@@ -28,6 +28,26 @@
 }
 
 se_policy_conf {
+    name: "32.0_product_pub_policy.conf",
+    srcs: [
+        ":se_build_files{.plat_public_32.0}",
+        ":se_build_files{.system_ext_public_32.0}",
+        ":se_build_files{.product_public_32.0}",
+        ":se_build_files{.reqd_mask}",
+    ],
+    installable: false,
+    build_variant: "user",
+}
+
+se_policy_cil {
+    name: "32.0_product_pub_policy.cil",
+    src: ":32.0_product_pub_policy.conf",
+    filter_out: [":reqd_policy_mask.cil"],
+    secilc_check: false,
+    installable: false,
+}
+
+se_policy_conf {
     name: "32.0_plat_policy.conf",
     srcs: [
         ":se_build_files{.plat_public_32.0}",