fix(dynamodb): service cannot start if table already exists

Now since the container might be reused across simulator updates, we need to make sure we clean up the table before it's being created.

dynamodb/dynamodb.sim.w

@@ -139,6 +139,10 @@ pub class Table_sim impl dynamodb_types.ITable {
         return  nil;
       })();
 
+      // delete the table if it already exists
+      try { client.deleteTable({ TableName: tableName }); } 
+      catch e { }
+
       util.waitUntil(() => {
         try {
           client.createTable({