--save_smaller flag is broken

The flag works exactly once, for subsequent smaller crashes with the same signature, the crash file is never updated. See the following log:

```
Sz:512 Tm:53780us (i/b/h/e/p/c) New:0/0/1/0/0/0, Cur:0/0/0/0/0/0
Crash: overwriting '/out/crashes/SIGABRT.PC.7ffff7900a7c.STACK.1a4fe4347c.CODE.-6.ADDR.0.INSTR.mov____%eax,%r13d.fuzz' (old 819 bytes, new 600 bytes)
Crash: saved as '/out/crashes/SIGABRT.PC.7ffff7900a7c.STACK.1a4fe4347c.CODE.-6.ADDR.0.INSTR.mov____%eax,%r13d.fuzz'
[2022-05-16T18:28:52+0000][W][14] subproc_checkTimeLimit():532 pid=1177 took too much time (limit 10 s). Killing it with SIGKILL
Crash: overwriting '/out/crashes/SIGABRT.PC.7ffff7900a7c.STACK.1a4fe4347c.CODE.-6.ADDR.0.INSTR.mov____%eax,%r13d.fuzz' (old 819 bytes, new 760 bytes)
Crash: saved as '/out/crashes/SIGABRT.PC.7ffff7900a7c.STACK.1a4fe4347c.CODE.-6.ADDR.0.INSTR.mov____%eax,%r13d.fuzz'
```

The command line options were: `honggfuzz -i /corpus -o /out/corpus --crashdir /out/crashes --linux_perf_ipt_block -t 10 --save_smaller --only_printable -- <...>`

The filesystem also only contains the file with 819 bytes.

EDIT: It seems that additionally the counting of unique bugs breaks when this flag is enabled.