Deduplicate tree building: call build_*_tree with 1 or 0 args.

app/controllers/application_controller/explorer.rb

@@ -12,7 +12,10 @@ def build_replaced_trees(replace_trees, valid_values)
   def try_build_tree(tree_symbol)
     method_name = "build_#{tree_symbol}_tree"
     return unless respond_to?(method_name, true)
-    method(method_name).call(tree_symbol)
+    build_method = method(method_name)
+    # FIXME: This is temporary, we actually need to remove all the build_*_tree methods and
+    # use the Feature::build_tree instead.
+    build_method.arity == 1 ? build_method.call(tree_symbol) : build_method.call
   end
 
   # Historical tree item selected