Off-by-one error for gethostname() in shmem_perf common code

[markbrown314]

test/performance/shmem_perf_suite/common.h:check_hostname_validation()

    int hostname_size = MAX_HOSTNAME_LEN;
    int i, errors = 0;

    char *hostname = (char *) shmem_malloc (hostname_size * sizeof(char));
    char *dest = (char *) shmem_malloc (my_info->num_pes * hostname_size *
                                        sizeof(char));

    if (hostname == NULL || dest == NULL) {
        fprintf(stderr, "shmem_malloc failed to allocate for hostname strings\n");
        return -1;
    }

    hostname_status = gethostname(hostname, hostname_size);
    if (hostname_status != 0) {
        fprintf(stderr, "gethostname failed (%d)\n", hostname_status);
        return -1;
    }

The issue is MAX_HOSTNAME_LEN is the maximum total characters of the hostname not including the end of string character '\0'. If the hostname happens to be 64 characters long, gethostname() would return an error and shmem_runtime_util_put_hostname() would state error "gethostname failed (-1)"

The input length parameter needs to be set to MAX_HOSTNAME_LEN+1