accounts: resolve error-prone warnings

 - missing @Override annotations
 - inner classes should be static if possible

Bug: 38496625
Test: build
Change-Id: Ic6a647b894036266dfa8f9908cec6049952cd38d
diff --git a/services/core/java/com/android/server/accounts/AccountManagerService.java b/services/core/java/com/android/server/accounts/AccountManagerService.java
index 36c3f7d..511c9de 100644
--- a/services/core/java/com/android/server/accounts/AccountManagerService.java
+++ b/services/core/java/com/android/server/accounts/AccountManagerService.java
@@ -4944,6 +4944,7 @@
                 this.userDebugDbInsertionPoint = userDebugDbInsertionPoint;
             }
 
+            @Override
             public void run() {
                 SQLiteStatement logStatement = userAccount.statementForLogging;
                 logStatement.bindLong(1, accountId);
@@ -6060,7 +6061,7 @@
         }
     }
 
-    private class NotificationId {
+    private static class NotificationId {
         final String mTag;
         private final int mId;