Convert selinux_policy to Android.bp

Bug: 350881031
Test: m selinux_policy
Test: m droidcore
Test: m
(Can get selinux_policy under out: out/target/product/vsoc_x86_64/fake_packages/selinux_policy-timestamp)

Change-Id: I9c4ebf40579e1ad466921e78c398f209252c210a
diff --git a/Android.bp b/Android.bp
index 7d36b86..f214253 100644
--- a/Android.bp
+++ b/Android.bp
@@ -1162,3 +1162,22 @@
         default: [],
     }),
 }
+
+phony {
+    name: "selinux_policy",
+    required: [
+        // Runs checkfc against merged service_contexts files
+        "merged_hwservice_contexts_test",
+        "merged_service_contexts_test",
+        "selinux_policy_nonsystem",
+        "selinux_policy_system",
+    ],
+}
+
+// selinux_policy is a main goal and triggers lots of tests.
+// Most tests are FAKE modules, so aren'triggered on normal builds. (e.g. 'm')
+// By setting as droidcore's dependency, tests will run on normal builds.
+phony_rule {
+    name: "droidcore",
+    phony_deps: ["selinux_policy"],
+}