Revert^2 "Set container to system for aconfig_declarations in AconfigFlags.bp"

This reverts commit 02287dc9e3dcf1fef015ca0db73d595800386f25.

Reason for revert: Performance regression is gone based on go/abtd verification, reintroduce the change.

Change-Id: I0dceae0d564612925f23002ac76fb60bbbe599f1
diff --git a/services/autofill/bugfixes.aconfig b/services/autofill/bugfixes.aconfig
index 590a1ef..0c3d40d 100644
--- a/services/autofill/bugfixes.aconfig
+++ b/services/autofill/bugfixes.aconfig
@@ -1,4 +1,5 @@
 package: "android.service.autofill"
+container: "system"
 
 flag {
   name: "test"
diff --git a/services/autofill/features.aconfig b/services/autofill/features.aconfig
index c130cee..1dc3b73 100644
--- a/services/autofill/features.aconfig
+++ b/services/autofill/features.aconfig
@@ -1,4 +1,5 @@
 package: "android.service.autofill"
+container: "system"
 
 flag {
   name: "autofill_credman_integration"