mlog_write_initial_log_record_fast(): Remove the buf_block_align() call
unless #ifdef UNIV_DEBUG.

btr_cur_update_in_place(): Replace buf_frame_get_page_zip() with
buf_block_get_page_zip().

btr_page_create(), btr_page_empty(): Replace the parameter page with block.

btr_attach_half_pages(): Use btr_block_get() instead of btr_page_get().
Remove buf_block_align() calls.

btr_cur_latch_leaves(): Remove duplicated code.  Use btr_block_get()
instead of btr_page_get().  Remove buf_block_align() calls.