analyze-migration.py: Remove trick on parsing ramblocks

RAM_SAVE_FLAG_MEM_SIZE contains the total length of ramblock idstr to know
whether scanning of ramblocks is complete.  Drop the trick.

Reviewed-by: Fabiano Rosas <farosas@suse.de>
Link: https://lore.kernel.org/r/20240117075848.139045-4-peterx@redhat.com
Signed-off-by: Peter Xu <peterx@redhat.com>
1 file changed