This is a followup patch.

Problem:
There is no call on Sys_var_integer::do_check() for 'set xxx=default';
The predefined default for parser_max_mem_size is "infinite".
This means that clients could simply do "set parser_max_mem_size=DEFAULT"
and get an "infinite" limit, even if the server was started with the option
--maximum-parser-max-mem-size=<some number>

This patch looks at max_system_variables.parser_max_mem_size after all
This is a followup patch.

Problem:
There is no call on Sys_var_integer::do_check() for 'set xxx=default';
The predefined default for parser_max_mem_size is "infinite".
This means that clients could simply do "set parser_max_mem_size=DEFAULT"
and get an "infinite" limit, even if the server was started with the option
--maximum-parser-max-mem-size=<some number>

This patch looks at max_system_variables.parser_max_mem_size after all
options have been parsed, and updates default value for
parser_max_mem_size accordingly.
Also update global_system_variables, so 'SELECT parser_max_mem_size'
reports correct data.