Remove unnecessary array conversion in log_array

This method is only ever called with an array since
0b2c49aa4d.

actionpack/lib/action_dispatch/middleware/debug_exceptions.rb

@@ -149,9 +149,7 @@ module ActionDispatch
         log_array(logger, message)
       end
 
-      def log_array(logger, array)
-        lines = Array(array)
-
+      def log_array(logger, lines)
         return if lines.empty?
 
         if logger.formatter && logger.formatter.respond_to?(:tags_text)