FindVulkan: Add support for cross-compiling between Windows x64/ARM64

The LunarG Vulkan SDK on Windows provides arch-specific library directories for cross-compiling. On X64 hosts it provides -ARM64 directories. On ARM64 hosts it provides -X64 directories.

It also provides arch-specific bin directories, but only for the .dlls of the cross architecture. We still want the plain bin directory containing host-architecture executable tools.

Co-authored-by: Giancane, Francesco <fgiancan@qti.qualcomm.com>
Co-authored-by: Arnaud, Adrien <aarnaud@qti.qualcomm.com>
Tested-by: Giancane, Francesco <fgiancan@qti.qualcomm.com>
Tested-by: Arnaud, Adrien <aarnaud@qti.qualcomm.com>
Backport: release