File system counters

File system counters display soft report symbols and maps to external variables.

Soft Report Symbol Counter Mapping to an external variable
filesys.reads fs_stat.rds MPE only
filesys.writes fs_stat.wts MPE only
filesys.rd_miss_rand fs_stat.rd_miss_rand MPE only
filesys.rd_miss_seq fs_stat.rd_miss_seq MPE only
filesys.wt_miss_rand fs_stat.wt_miss_rand MPE only
filesys.wt_miss_seq fs_stat.wt_miss_seq MPE only