MDEV-22871 tried to optimize the buf_page_t initialization in
buf_page_init_for_read() by initializing everything while the block
is in freed state, and only afterwards attaching the block to
buf_pool.page_hash.

In an rr replay trace, we have multiple threads executing in
buf_page_optimistic_get() on the same buf_block_t while the block is
being freed and reallocated several times in buf_page_init_for_read().
Because also the buf_page_t::id() is changing, the buf_pool.page_hash
is being protected by a different rw-lock than the one that
buf_page_optimistic_get() are successfully read-locking.

buf_page_optimistic_get(): Validate also buf_page_t::id() after
acquiring the buf_pool.page_hash latch.

Reviewed by: Thirunarayanan Balathandayuthapani