honggfuzz persistent fuzzing mode subproc_checkTimeLimit took too much time

Trying to fuzz simple test target.
```C
#include
#include
#include
#include
#include
#include
extern HF_ITER(uint8_t** buf, size_t* len);
void test(char* buf){
if (buf[0] == 'f') {
if (buf[1] == 'o') {
if (buf[2] == 'o') {
if (buf[3] == '!') {
abort();
}
}
}
}
}
int main(void) {
for (;;) {
size_t len;
uint8_t *buf;

HF_ITER(&buf, &len);
test(buf);

}
return 0;
}
```

hfuzz_cc/hfuzz-clang test.c -o test
honggfuzz -i in -n 1 -P -- ./test
```
------------------------[ 0 days 00 hrs 00 mins 10 secs ]----------------------
Iterations : 10
Mode [1/3] : Feedback Driven Dry Run [4/16]
Target : ./test
Threads : 1, CPUs: 80, CPU%: 7% [0%/CPU]
Speed : 0/sec [avg: 1]
Crashes : 0 [unique: 0, blocklist: 0, verified: 0]
Timeouts : 9 [1 sec]
Corpus Size : 5, max: 8,192 bytes, init: 16 files
Cov Update : 0 days 00 hrs 00 mins 04 secs ago
Coverage : edge: 2/8 [25%] pc: 0 cmp: 8
---------------------------------- [ LOGS ] ------------------/ honggfuzz 2.4 /-

Entering phase 1/3: Dry Run
Launched new fuzzing thread, no. #0
Persistent mode: Launched new persistent pid=41178
[2021-03-11T11:02:21+0800][W][41176] subproc_checkTimeLimit():531 pid=41178 took too much time (limit 1 s). Killing it with SIGKILL
[2021-03-11T11:02:21+0800][W][41176] arch_checkWait():239 Persistent mode: pid=41178 exited with status: SIGNALED, signal: 9 (Killed)
Sz:4 Tm:1,000,679us (i/b/h/e/p/c) New:0/0/0/2/0/0, Cur:0/0/0/2/0/0
Persistent mode: Launched new persistent pid=41179
[2021-03-11T11:02:22+0800][W][41176] subproc_checkTimeLimit():531 pid=41179 took too much time (limit 1 s). Killing it with SIGKILL
[2021-03-11T11:02:22+0800][W][41176] arch_checkWait():239 Persistent mode: pid=41179 exited with status: SIGNALED, signal: 9 (Killed)
Sz:8 Tm:1,099,688us (i/b/h/e/p/c) New:0/0/0/0/0/2, Cur:0/0/0/0/0/2
Persistent mode: Launched new persistent pid=41180
[2021-03-11T11:02:23+0800][W][41176] subproc_checkTimeLimit():531 pid=41180 took too much time (limit 1 s). Killing it with SIGKILL
[2021-03-11T11:02:23+0800][W][41176] arch_checkWait():239 Persistent mode: pid=41180 exited with status: SIGNALED, signal: 9 (Killed)
Sz:8 Tm:1,100,015us (i/b/h/e/p/c) New:0/0/0/0/0/2, Cur:0/0/0/0/0/2
Persistent mode: Launched new persistent pid=41186
[2021-03-11T11:02:24+0800][W][41176] subproc_checkTimeLimit():531 pid=41186 took too much time (limit 1 s). Killing it with SIGKILL
[2021-03-11T11:02:24+0800][W][41176] arch_checkWait():239 Persistent mode: pid=41186 exited with status: SIGNALED, signal: 9 (Killed)
Sz:4 Tm:1,099,926us (i/b/h/e/p/c) New:0/0/0/0/0/2, Cur:0/0/0/0/0/2
Persistent mode: Launched new persistent pid=41187
[2021-03-11T11:02:25+0800][W][41176] subproc_checkTimeLimit():531 pid=41187 took too much time (limit 1 s). Killing it with SIGKILL
[2021-03-11T11:02:25+0800][W][41176] arch_checkWait():239 Persistent mode: pid=41187 exited with status: SIGNALED, signal: 9 (Killed)
Persistent mode: Launched new persistent pid=41189
[2021-03-11T11:02:26+0800][W][41176] subproc_checkTimeLimit():531 pid=41189 took too much time (limit 1 s). Killing it with SIGKILL
[2021-03-11T11:02:26+0800][W][41176] arch_checkWait():239 Persistent mode: pid=41189 exited with status: SIGNALED, signal: 9 (Killed)
Sz:8 Tm:1,100,160us (i/b/h/e/p/c) New:0/0/0/0/0/2, Cur:0/0/0/0/0/2
Persistent mode: Launched new persistent pid=41190
[2021-03-11T11:02:27+0800][W][41176] subproc_checkTimeLimit():531 pid=41190 took too much time (limit 1 s). Killing it with SIGKILL
[2021-03-11T11:02:27+0800][W][41176] arch_checkWait():239 Persistent mode: pid=41190 exited with status: SIGNALED, signal: 9 (Killed)
Persistent mode: Launched new persistent pid=41191
[2021-03-11T11:02:28+0800][W][41176] subproc_checkTimeLimit():531 pid=41191 took too much time (limit 1 s). Killing it with SIGKILL
[2021-03-11T11:02:28+0800][W][41176] arch_checkWait():239 Persistent mode: pid=41191 exited with status: SIGNALED, signal: 9 (Killed)
Persistent mode: Launched new persistent pid=41192
[2021-03-11T11:02:29+0800][W][41176] subproc_checkTimeLimit():531 pid=41192 took too much time (limit 1 s). Killing it with SIGKILL
[2021-03-11T11:02:29+0800][W][41176] arch_checkWait():239 Persistent mode: pid=41192 exited with status: SIGNALED, signal: 9 (Killed)
Persistent mode: Launched new persistent pid=41194
Signal 2 (Interrupt) received, terminating
Terminating thread no. #0, left: 0
Summary iterations:10 time:10 speed:1 crashes_count:0 timeout_count:9 new_units_added:0 slowest_unit_ms:1100 guard_nb:8 branch_coverage_percent:25 peak_rss_mb:5
```
Host machine is RH2288 with 40 cores, os is ubuntu 18.04.