Double check if bat is necessary

Author: josevalim

lib/mix/lib/mix/tasks/deps.partition.ex

@@ -21,7 +21,7 @@ defmodule Mix.Tasks.Deps.Partition do
 
   defp server(socket, deps, count, force?) do
     elixir =
-      System.find_executable("elixir") ||
+      System.find_executable("elixir") || System.find_executable("elixir.bat") ||
         raise "cannot find elixir executable for partition compilation"
 
     {:ok, {ip, port}} = :inet.sockname(socket)