relocate android.util.base64.* -> android.util.*

b/2553469 - API REVIEW: android.util.base64

Change-Id: I6a514032152a8b1899db52d020aca8e8b19e74e9
diff --git a/preloaded-classes b/preloaded-classes
index 5672c66..a2c1f68 100644
--- a/preloaded-classes
+++ b/preloaded-classes
@@ -468,6 +468,7 @@
 android.text.style.TextAppearanceSpan
 android.text.util.Linkify
 android.util.AttributeSet
+android.util.Base64$Encoder
 android.util.DisplayMetrics
 android.util.EventLog
 android.util.EventLog$Event
@@ -481,7 +482,6 @@
 android.util.TypedValue
 android.util.Xml
 android.util.Xml$Encoding
-android.util.base64.Base64$Encoder
 android.view.AbsSavedState
 android.view.ContextThemeWrapper
 android.view.Display