Add validators for all Settings.Secure settings that are backed up

A few no longer used settings were removed from SETTINGS_TO_BACKUP.

And extend the unit test to fail if new ones are added without
a validator. Also fail to boot in that case.

Ref: go/android-p-backed-up-settings
Test: atest frameworks/base/core/tests/coretests/src/android/provider/SettingsValidatorsTest.java
Bug: 64988620
Change-Id: I94b4039c9f54c341aec72b62579be3dd8bd84dbb
diff --git a/core/tests/coretests/src/android/provider/SettingsBackupTest.java b/core/tests/coretests/src/android/provider/SettingsBackupTest.java
index 8da7ced..e748e64 100644
--- a/core/tests/coretests/src/android/provider/SettingsBackupTest.java
+++ b/core/tests/coretests/src/android/provider/SettingsBackupTest.java
@@ -533,7 +533,9 @@
                  Settings.Secure.VOICE_RECOGNITION_SERVICE,
                  Settings.Secure.INSTANT_APPS_ENABLED,
                  Settings.Secure.BACKUP_MANAGER_CONSTANTS,
-                 Settings.Secure.KEYGUARD_SLICE_URI);
+                 Settings.Secure.KEYGUARD_SLICE_URI,
+                 Settings.Secure.PARENTAL_CONTROL_ENABLED,
+                 Settings.Secure.PARENTAL_CONTROL_REDIRECT_URL);
 
     @Test
     public void systemSettingsBackedUpOrBlacklisted() {