JsonConf handles Unicode path/value wrong on Win32
<h3><details><summary>Original Reporter info from Mantis: <small>Alextp</small></summary><small>
- **Reporter name:** CudaText man
</small></details></h3>
## Description:
I tested on last FPC trunk fpJson version.<br/>
On each reading/writing a Unicode json path/value, I see corrupted enc in resulting json file.
Demo app writes file t.json in its folder. Each button press makes file bad.
## Mantis conversion info:
- **Mantis ID:** 35113
- **Platform:** Win10, Win7 x64
- **Version:** 3.3.1
- **Fixed in version:** 3.3.1
- **Fixed in revision:** 41473 (#970188907efc398777cbcefade890e37d61a4bed)
- **Target version:** 3.2.0
issue