QSysInfo::currentCpuArchitecture() is incorrect on ARM64 Windows

When using an x86 application running under emulation on Windows on ARM, QSysInfo::currentCpuArchitecture() doesn't return "arm64" as it should.

This is (partially) because GetNativeSystemInfo(), which is used to determine the CPU architecture, doesn't actually return the real native architecture details on ARM64. This is documented in the MSDN page for GetNativeSystemInfo().

In order to get accurate information about the native architecture of ARM systems, you must use the newer IsWow64Process2() which returns accurate results for non-Intel architectures.