Add untrusted_app_27

This is a partial cherry pick of commit 6231b4d9
'Enforce per-app data protections for targetSdk 28+'.

Untrusted_app_27 remains unreachable, but it's existence
prevents future merge conflicts.

Bug: 63897054
Test: build/boot aosp_walleye-userdebug
Change-Id: I64b013874fe87b55f47e817a1279e76ecf86b7c0
Merged-In: I64b013874fe87b55f47e817a1279e76ecf86b7c0
(cherry picked from commit 6231b4d9fc98bb42956198e9f54cabde69464339)
diff --git a/private/compat/26.0/26.0.ignore.cil b/private/compat/26.0/26.0.ignore.cil
index 403fde7..cfda748 100644
--- a/private/compat/26.0/26.0.ignore.cil
+++ b/private/compat/26.0/26.0.ignore.cil
@@ -109,6 +109,7 @@
     traced_probes_tmpfs
     traced_producer_socket
     traced_tmpfs
+    untrusted_app_all_devpts
     update_engine_log_data_file
     vendor_default_prop
     usbd
@@ -131,4 +132,6 @@
 ;;     Thus, these types are also not mapped, but recorded for checkapi tests
 (typeattribute priv_objects)
 (typeattributeset priv_objects
-     ( adbd_tmpfs ))
+     ( adbd_tmpfs
+       untrusted_app_27_tmpfs
+     ))