Test build on 0.3.6: file I/O into game memory

Unofficial test build, not a release from SuperMedo. It replaces two files of 0.3.6; everything else stays.

It is 0.3.6 plus one commit, fix/guest-io (1274d36):

• File I/O into game memory without faults or short reads. Reads and writes go through a second view of game memory that page protection can't block. The GPU side is involved only for pages it actually tracks, exactly where the game's own access would have faulted; other file buffers cost nothing extra. 0.3.6 retries short reads (Supermedo#101); this removes the cause, and also covers writes from pages the GPU made inaccessible.
• Split flexible memory no longer frees pages still in use. Unmapping part of a flexible mapping freed and zeroed the left part's physical pages, which could leave two allocations sharing memory.

The GPU merge is not changed: 0.3.6 already fixes the London pub crash without a performance cost. (The earlier test build removed the merge, and that is what cost frame rate.)

Install

1. Back up bin\bb-probe.exe and bin\libc++.dll in your uncharted-windows 0.3.6 folder.
2. Extract the zip into uncharted-windows, overwriting both. (libc++.dll is a newer build of the C++ runtime that the new exe needs; checked against every other DLL of 0.3.6.)

To undo, restore the two files.

Please report

• FPS in the same spot with 0.3.6 and with this build, ideally with BB_FRAME_STATS=1 in the launcher's "Environment" field.
• Any crash, with user\last_run.log.

Checked here: builds from 1274d36, guest-io-test passes, the imported DLLs are the same as 0.3.6's, and bb-probe.exe --vulkan-only passes inside the 0.3.6 package. Not yet played.

SHA-256 of the zip: 6def41270eed4b68eff3ea5b004393c213703f51f8b9bcb6e768a57c12d77a42