Add microdroid sepolicy test support

MicrodroidHostTestCases will pull the VM's sepolicy and check it against
system/sepolicy/microdroid's neverallow rules, using sepolicy-analyze
tool.

Bug: 218461215
Test: atest MicrodroidHostTestCases
Change-Id: I62a69053996b71d69dd2bf6b7eabc8b701095477
diff --git a/microdroid/Android.bp b/microdroid/Android.bp
index 2e8766c..0600207 100644
--- a/microdroid/Android.bp
+++ b/microdroid/Android.bp
@@ -280,3 +280,11 @@
     relative_install_path: "selinux",
     installable: false,
 }
+
+// For CTS
+se_policy_conf {
+    name: "microdroid_general_sepolicy.conf",
+    srcs: system_policy_files,
+    exclude_build_test: true,
+    installable: false,
+}