wineopenxr: Implement Win32 performance counter time conversion functions for MSFS2020 VR Controller Tracking

Implements both xrConvertWin32PerformanceCounterToTimeKHR and xrConvertTimeToWin32PerformanceCounterKHR for converting between QueryPerformanceCounter ticks and XrTime nanoseconds. Fixes VR controller tracking in Microsoft Flight Simulator 2020, where controllers would spawn at the HMD position due to failed time conversion. Debug logs showed these functions being called every frame for pose timing.