BUG#58858 : sys_vars.innodb_max_dirty_pages_pct_func fails sporadically

Committing After latest merge.      
Modified check_pct procedure to check return value of wait condition instead 
of calling "dirty_pct".
   
Adding Review comments:
1) Added comment for success variable value
2) Procedure check_pct changed For Adding BOOLEAN input and SELECT QUERY Change