bugfix: clear the stack on set_map_item

miden-lib/asm/miden/account.masm

@@ -101,7 +101,7 @@ export.set_item
     # => [R', V]
 end
 
-#! Gets a map item from the account storage. Panics if 
+#! Gets a map item from the account storage. Panics if
 #! - the index for the map is out of bounds, means >255
 #! - the slot item at index is not a map
 #!
@@ -120,12 +120,12 @@ export.get_map_item
     # => [VALUE, 0]
 end
 
-#! Sets a map item in the account storage. Panics if 
+#! Sets a map item in the account storage. Panics if
 #! - the index for the map is out of bounds, means >255
 #! - the slot item at index is not a map
 #!
 #! Stack: [index, KEY, VALUE]
-#! Output: [OLD_MAP_ROOT, OLD_MAP_VALUE, 0]
+#! Output: [OLD_MAP_ROOT, OLD_MAP_VALUE]
 #!
 #! - index is the index of the map where the KEY VALUE should be set.
 #! - KEY is the key to set at VALUE.
@@ -134,11 +134,10 @@ end
 #! - OLD_MAP_VALUE is the old value at KEY.
 export.set_map_item
     syscall.set_account_map_item
-    # => [OLD_MAP_ROOT, OLD_MAP_VALUE]
-
-    # prepare stack for return
-    push.0 movdn.9
     # => [OLD_MAP_ROOT, OLD_MAP_VALUE, 0]
+
+    movup.8 drop
+    # => [OLD_MAP_ROOT, OLD_MAP_VALUE]
 end
 
 #! Sets the code of the account the transaction is being executed against. This procedure can only