Update bench_tester.py

1) Reading hexadecimal address 'system_address_call' of the system() from file 'addresses' fixed 
2) Reading hexadecimal address of the shell 'shell_address_call' is added when ASLR (from file 'addresses_ASLR_ON' )
3) Output of the subprocess  
p = subprocess.Popen(["./ncompress/src/ncompress", malinputhex], stdout=subprocess.PIPE, stderr=subprocess.STDOUT)
is redirected to file  /tmp/bench_log
4) Version is written to the log file /tmp/bench even if the file already exists. It is required for the log file by 
log=mmap.mmap(f.fileno(), 0, access=mmap.ACCESS_READ) 
to be non-empty
5) In the initialization section attacking string has been changed to non-attacking string. This initial call of teh application is only required to create files of addresses, no need to run attack in this case