Comment 4 for bug 1305364

Note to self what needs fixing (both potentially serious issues and merely better asserts) in 5.5:
    - buf_flush_or_remove_pages: add mutex_own LRU list mutex
    - buf_flush_page_and_try_neighbors: BUF_BLOCK_REMOVE_HASH => LRU
      mutex held
    - buf_LRU_free_from_common_LRU_list must have an LRU mutex, check
      its caller too
    - buf_page_get_zip must check for BUF_BLOCK_REMOVE_HASH before
      calling buf_LRU_free_block
    - buf_pool_watch_is_sentinel: assert that either page mutex is
      locked, or that page hash is S or X latched.
    - buf_read_ahead_random must latch page hash.
    - buf_page_get_block: assert page hash latched.