Improve JS Exception handling.
- Check for pending exceptions after function calls and script executions.
- Call LOGERROR instead of JS_ReportError when there is a conversion error in FromJSVal, since that can only be called from C++ (where JS errors don't really make sense). Instead, C++ callers of FromJSVal should handle the failure and, themselves, either report an error or simply do something else.
- Wrap JS_ReportError since that makes updating it later easier.
This isn't a systematical fix since ToJSVal also ought return a boolean for failures, and we probably should trigger errors instead of warnings on 'implicit' conversions, rather a preparation diff.
Part of the SM52 migration, stage: SM45 compatible (actually SM52 incompatible, too).
Based on a patch by: Itms
Comments by: Vladislavbelov, Stan`
Differential Revision: https://code.wildfiregames.com/D3093