Add NtAllocateVirtualMemory & NtFreeVirtualMemory to std.os.windows / std.os.windows.ntdll + missing memory constants

[ziggoon]

This commit adds two new NTDLL functions: NtAllocateVirtualMemory and NtFreeVirtualMemory to the standard library. Additionally, two constants used for memory allocations were added: MEM_RESERVE_PLACEHOLDER and MEM_PRESERVE_PLACEHOLDER.

Relevant issue: #22846

[andrewrk]

Good first step. Do they work?

[ziggoon]

Good first step. Do they work?

I have some initial tests for the page allocator changes working locally. Working on establishing some solid benchmarks between the proposed changes and previous implementation which will be provided in the original issue. See relevant test logs below:

C:\Users\ziggoon\Downloads>".\page_allocator_test(1).exe"
Testing PageAllocator on Windows
Allocated 4096 bytes at address u8@16ba8480000
Memory initialized with 0xAA
Memory verification: SUCCESS
Allocated 8192 bytes at aligned address u8@16ba8490000
Address is aligned to 16 bytes: true
Directly allocated 16384 bytes at address u8@16ba84a0000
Direct allocation address is aligned to 64 bytes: true
Allocated resizable memory of 4096 bytes at u8@16ba84b0000
Resized to 8192 bytes at u8@16ba84c0000
Original data preserved after resize: SUCCESS
All tests completed!