locksrv: Remove redundant stat() calls in isr_srv_stat.pl
locksrv: Remove redundant stat() calls in isr_srv_stat.pl

- Make a single call to stat(), cache the results, and print from the cache,
rather than calling stat() 14 times

cmusatyalab/openisr,cmusatyalab/openisr,cmusatyalab/openisr,cmusatyalab/openisr,cmusatyalab/openisr