util: Add size to ralloc_header in debug mode

For 64-bit environments this just fills a padding.  Will enable
dumping more information when debugging ralloc trees.

Acked-by: Marek Olšák <marek.olsak@amd.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/25482>

src/util/ralloc.c

@@ -55,6 +55,7 @@ struct ralloc_header
 #ifndef NDEBUG
    /* A canary value used to determine whether a pointer is ralloc'd. */
    unsigned canary;
+   unsigned size;
 #endif
 
    struct ralloc_header *parent;
@@ -139,6 +140,7 @@ ralloc_size(const void *ctx, size_t size)
 
 #ifndef NDEBUG
    info->canary = CANARY;
+   info->size = size;
 #endif
 
    return PTR_FROM_HEADER(info);