changed strategy to reduce contention for region search and vs2019 project fix

src/memory.c

@@ -389,7 +389,7 @@ void* _mi_mem_alloc_aligned(size_t size, size_t alignment, bool* commit, bool* l
   // find a range of free blocks
   void* p = NULL;
   size_t count = mi_atomic_read(&regions_count);
-  size_t idx = 0; // tld->region_idx; // start at 0 to reuse low addresses? Or, use tld->region_idx to reduce contention?
+  size_t idx = tld->region_idx; // start at 0 to reuse low addresses? Or, use tld->region_idx to reduce contention?
   for (size_t visited = 0; visited < count; visited++, idx++) {
     if (idx >= count) idx = 0;  // wrap around
     if (!mi_region_try_alloc_blocks(idx, blocks, size, commit, large, is_zero, &p, id, tld)) return NULL; // error