client/mysqltest.c:
  Prepend the command to execute by system with "sh" to make it executed by cygwin's bash
mysql-test/t/mysqldump.test:
  Change from " to ' to avoid bash's filename expanding. I.e to avoid that "[mysqltest1]" will be llok for any dirs in mysql-test/* that are named m, y, s, q etc. And ther is actually one dir called t, so we will get a match and thus echo "t" to the file.