headers: check which version of UWP Windows contains Virtual functions

* VirtualFree is always available in UWP
* VirtualAlloc is only available since 19H1/18362 SDK
* VirtualAllocEx is only available since 20H1/19041 SDK

They are all found in api-ms-win-core-memory-l1-1-0 which is in mincore
and windowsapp. It's one of the target DLLs [1]

[1] https://learn.microsoft.com/en-us/uwp/win32-and-com/win32-apis#apis-from-api-ms-win-core-memory-l1-1-0dll

Signed-off-by: LIU Hao <lh_mouse@126.com>