ignoring --threads=1
**Describe the bug**
XMRig ignores `./xmrig --threads=1` and proceeds with 5 threads anyway

**To Reproduce**
Download lastest xmrig
Make a config file from XMRig.com wizard
run xmrig with `--threads=N` switch

**Expected behavior**
XMRig should proceed with 1 thread and CPU usage should go down to about ~100% (Only on core should be used)

**Required data**
 - Miner log as text or screenshot: Not sure what this is but it runs fine without error
 - Config file or command line (without wallets) https://pastebin.com/f9XUqkkL
 - OS: MacOS Catalina 10.15.7
 - For GPU related issues: information about GPUs and driver version.

**Additional context**
I have to manually control CPU uasage with AppPolice (https://github.com/AppPolice/AppPolice)
