Move Game Saving to Separate Thread (#2820)

* Refactor `Vec2f`, `Vec3f`, `Vec3s` in `z64math` to avoid reserved identifiers.

* Include `z64save` in SaveManager, which requires encapsulating `#include gameplaystats.h` and `InitStatTracker` in the cpp to fix compile issues.

Adds SaveContext reference parameters to SaveFunc and existing implementations in preparation for threaded saves.

* Threaded saves fully implemented.

Platform-specific save code removed.

Thread safety added. Will wait for thread pool tasks to finish before resetting or closing.

* Converted gSaveContext copy for save threads to the heap with `new`, deleted at the end of the threaded function to prevent possible issues with the stack.

* Turns out leaving the call to `ThreadPoolWait` in a `GameInteractor::OnExitGame` hook seems to be just fine.

* Removed unnecessary references to `SaveManager::ThreadPoolWait()`, game hooks are the only places it's called now.

* Re-added WiiU/Switch performance save code.

* Added call to `SaveManager::ThreadPoolWait` in `Sram_InitSave` to prevent trying to load a newly "created" save before the save file was actually written.

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Co-authored-by: Christopher Leggett <chris@leggett.dev>

soh/src/code/z_sram.c

@@ -222,6 +222,7 @@ void Sram_InitSave(FileChooseContext* fileChooseCtx) {
     }
 
     Save_SaveFile();
+    SaveManager_ThreadPoolWait();
 }
 
 void Sram_InitSram(GameState* gameState) {