Move initializations of environment variables that are constant during the whole testrun to 'environment_setup'
Split out functions that detects if we need master or slave restarts


mysql-test/lib/mtr_process.pl:
  Fix spelling error
mysql-test/mysql-test-run.pl:
  Move initializations of environment variables that are constant during the whole testrun to 'environment_setup'
  Split out functions 'run_testcase_need_master_restart' and 'run_testcase_need_slave_restart'