Common: Reduce LazyMemoryRegion's Windows block size

8 MiB is excessively large for the new use cases, and probably a bit
overkill for the old use cases too. Let's reduce it to 1 MiB.

Author: JosJuice

Source/Core/Common/MemArena.h

@@ -161,7 +161,7 @@ class MemArena final
 class LazyMemoryRegion final
 {
 public:
-  constexpr static size_t WINDOWS_BLOCK_SIZE = 8 * 1024 * 1024;  // size of allocated memory blocks
+  constexpr static size_t WINDOWS_BLOCK_SIZE = 1024 * 1024;  // size of allocated memory blocks
 
   LazyMemoryRegion();
   ~LazyMemoryRegion();