Add support for SI suffixes in SET statement for configuring size-related variables

There are several size-related system variables that can be changed dynamically. e.g.:

• innodb_log_file_size
• innodb_buffer_pool_size
• max_heap_table_size
• tmp_table_size
• tmp_disk_table_size
• binlog_cache_size
• binlog_file_cache_size
• binlog_stmt_cache_size
• etc.

In configuration files, users are able to set these variables using SI prefixes. e.g.:

[mariadb]

innodb_log_file_size=2G

It would be great if users could do the same thing with SET:

SET GLOBAL innodb_log_file_size='2G';

Currently, users would have to do this instead:

SET GLOBAL innodb_log_file_size=(2 * 1024 * 1024 * 1024);

Can we implement SI prefixes for SET?