perf: WPO/LTCG, fix potential memory leaks, reduce busy-waits, loop opts; general optimizations

Minecraft.Client/GameRenderer.h

@@ -128,8 +128,6 @@ private:
     void tickRain();
 private:
 	// 4J - brought forward from 1.8.2
-	float *rainXa;
-	float *rainZa;
 protected:
 	void renderSnowAndRain(float a);
     volatile int xMod;