- Use tmp sh file both in system and popen 


client/mysqltest.c:
  Introduce common functions to handle unix emulation on windows using a temporary sh file.
  Use it both in my_popen and my_system.
mysql-test/r/mysqltest.result:
  Update test result
mysql-test/t/mysqltest.test:
  Fix "windows paths" in three places that doesn't automatically get fixed
  Uset the output file mysqltest.sql instead of con.sql as con is not an allowed filename on Windows
  Use system for util functions