libbinder_ndk: Add stability downgrade

This can be used to allow registering a service with a VINTF interface
without requiring a manifest declaration.

This is useful for test services or in the case of a system proxy
service that implements the same interface as the vintf service.

Bug: 183154648
Bug: 177664629
Test: atest binderStabilityTest
Change-Id: Ibd8dad46945a339b77dca70484082fda06220ee3
diff --git a/libs/binder/ndk/libbinder_ndk.map.txt b/libs/binder/ndk/libbinder_ndk.map.txt
index f1db653..67c85b6 100644
--- a/libs/binder/ndk/libbinder_ndk.map.txt
+++ b/libs/binder/ndk/libbinder_ndk.map.txt
@@ -127,6 +127,9 @@
     AServiceManager_tryUnregister; # llndk
     AServiceManager_reRegister; # llndk
 
+    AIBinder_forceDowngradeToSystemStability; # apex
+    AIBinder_forceDowngradeToVendorStability; # llndk
+
     AIBinder_Class_getDescriptor;
     AIBinder_Weak_clone;
     AIBinder_Weak_lt;