Fix for out-of-bound accessing last free block in EXTENSIVE defragmentation algorithm. Code by @medranSolus See #232

diff --git a/include/vk_mem_alloc.h b/include/vk_mem_alloc.h
index c424ab9..7525264 100644
--- a/include/vk_mem_alloc.h
+++ b/include/vk_mem_alloc.h

@@ -13289,7 +13289,7 @@
                                 VMA_SWAP(vector->m_Blocks[i], vector->m_Blocks[vector->GetBlockCount() - ++m_ImmovableBlockCount]);

                                 if (state.firstFreeBlock != SIZE_MAX)

                                 {

-                                    if (i < state.firstFreeBlock - 1)

+                                    if (i + 1 < state.firstFreeBlock)

                                     {

                                         if (state.firstFreeBlock > 1)

                                             VMA_SWAP(vector->m_Blocks[i], vector->m_Blocks[--state.firstFreeBlock]);

@@ -13709,6 +13709,13 @@
     case StateExtensive::Operation::FindFreeBlockTexture:

     case StateExtensive::Operation::FindFreeBlockAll:

     {

+        // No more blocks to free, just perform fast realloc and move to cleanup

+        if (vectorState.firstFreeBlock == 0)

+        {

+            vectorState.operation = StateExtensive::Operation::Cleanup;

+            return ComputeDefragmentation_Fast(vector);

+        }

+

         // No free blocks, have to clear last one

         size_t last = (vectorState.firstFreeBlock == SIZE_MAX ? vector.GetBlockCount() : vectorState.firstFreeBlock) - 1;

         VmaBlockMetadata* freeMetadata = vector.GetBlock(last)->m_pMetadata;

@@ -13777,8 +13784,7 @@
             }

             vectorState.firstFreeBlock = last;

             // Nothing done, block found without reallocations, can perform another reallocs in same pass

-            if (prevMoveCount == m_Moves.size())

-                return ComputeDefragmentation_Extensive(vector, index);

+            return ComputeDefragmentation_Extensive(vector, index);

         }

         break;

     }