This includes fixing all utilities to not have any memory leaks,
as safemalloc warnings stopped tests from passing on MacOSX.

- Ensure that all clients takes character-set-dir, as the
  libmysqlclient library will use it.
- mysql-test-run now passes character-set-dir to all external clients.
- Changed dynstr_free() so that it can be called twice (made freeing code easier)
- Changed rpl_global_gtid_slave_state to be allocated dynamicly as it
  includes a mutex that needs to be initizlied/destroyed before my_end() is called.
- Removed rpl_slave_state::init() and rpl_slave_stage::deinit() as
  their job are better handling by constructor and delete.
- Print alias instead of table_name in check_duplicate_key as
  table_name may have been converted to lower case.

Other things:
- Fixed a case in time_to_datetime_with_warn() where we where
  using && instead of & in tests