py/gc: Be sure to count last allocated block at heap end in stats.

Previously, if there was chain of allocated blocks ending with the last
block of heap, it wasn't included in number of 1/2-block or max block
size stats.

py/gc.c

@@ -327,18 +327,9 @@ void gc_info(gc_info_t *info) {
     info->num_1block = 0;
     info->num_2block = 0;
     info->max_block = 0;
-    for (size_t block = 0, len = 0; block < MP_STATE_MEM(gc_alloc_table_byte_len) * BLOCKS_PER_ATB; block++) {
+    bool finish = false;
+    for (size_t block = 0, len = 0; !finish;) {
         size_t kind = ATB_GET_KIND(block);
-        if (kind == AT_FREE || kind == AT_HEAD) {
-            if (len == 1) {
-                info->num_1block += 1;
-            } else if (len == 2) {
-                info->num_2block += 1;
-            }
-            if (len > info->max_block) {
-                info->max_block = len;
-            }
-        }
         switch (kind) {
             case AT_FREE:
                 info->free += 1;
@@ -359,6 +350,24 @@ void gc_info(gc_info_t *info) {
                 // shouldn't happen
                 break;
         }
+
+        block++;
+        finish = (block == MP_STATE_MEM(gc_alloc_table_byte_len) * BLOCKS_PER_ATB);
+        // Get next block type if possible
+        if (!finish) {
+            kind = ATB_GET_KIND(block);
+        }
+
+        if (finish || kind == AT_FREE || kind == AT_HEAD) {
+            if (len == 1) {
+                info->num_1block += 1;
+            } else if (len == 2) {
+                info->num_2block += 1;
+            }
+            if (len > info->max_block) {
+                info->max_block = len;
+            }
+        }
     }
 
     info->used *= BYTES_PER_BLOCK;