Changed static const in Alter_info and Alter_online_info to defines

Main reason was to make it easier to print the above structures in
a debugger. Additional benefits is that I was able to use same
defines for both structures, which simplifes some code.

Most of the code is just removing Alter_info:: and Alter_inplace_info::
from alter table flags.

Following renames was done:
HA_ALTER_FLAGS        -> alter_table_operations
CHANGE_CREATE_OPTION  -> ALTER_CHANGE_CREATE_OPTION
Alter_info::ADD_INDEX -> ALTER_ADD_INDEX
DROP_INDEX            -> ALTER_DROP_INDEX
ADD_UNIQUE_INDEX      -> ALTER_ADD_UNIQUE_INDEX
DROP_UNIQUE_INDEx     -> ALTER_DROP_UNIQUE_INDEX
ADD_PK_INDEX          -> ALTER_ADD_PK_INDEX
DROP_PK_INDEX         -> ALTER_DROP_PK_INDEX
Alter_info:ALTER_ADD_COLUMN    -> ALTER_PARSE_ADD_COLUMN
Alter_info:ALTER_DROP_COLUMN   -> ALTER_PARSE_DROP_COLUMN
Alter_inplace_info::ADD_INDEX  -> ALTER_ADD_NON_UNIQUE_NON_PRIM_INDEX
Alter_inplace_info::DROP_INDEX -> ALTER_DROP_NON_UNIQUE_NON_PRIM_INDEX

Other things:
- Added typedef alter_table_operatons for alter table flags
- DROP CHECK CONSTRAINT can now be done online
- Added checks for Aria tables in alter_table_online.test
- alter_table_flags now takes an ulonglong as argument.
- Don't support online operations if checksum option is used.
- sql_lex.cc doesn't add ALTER_ADD_INDEX if index is not created

storage/mroonga/mrn_table.hpp

@@ -96,7 +96,7 @@ struct st_mrn_slot_data
 };
 
 #define MRN_SET_WRAP_ALTER_KEY(file, ha_alter_info) \
-  Alter_inplace_info::HA_ALTER_FLAGS base_handler_flags = ha_alter_info->handler_flags; \
+  alter_table_operations base_handler_flags = ha_alter_info->handler_flags; \
   KEY  *base_key_info_buffer = ha_alter_info->key_info_buffer; \
   uint base_key_count = ha_alter_info->key_count; \
   uint base_index_drop_count = ha_alter_info->index_drop_count; \