Replace btr_page_get_level() with page_is_leaf() where possible.
row_purge_upd_exist_or_extern(): Remove obsolete TODO comment.
dtuple_convert_big_rec(): Replace a flag variable with goto.
of clustered indexes. Previously, parts of the code assumed that these
columns would exist on all leaf pages. Simplify the update-in-place of
these columns.
Add inline function dict_index_is_clust() to replace all tests
index->type & DICT_CLUSTERED.
Remove the redo log entry types MLOG_ZIP_WRITE_TRX_ID and
MLOG_ZIP_WRITE_ROLL_PTR, because the modifications to these columns
are covered by logical logging.
Fuse page_zip_write_trx_id() and page_zip_write_roll_ptr() into
page_zip_write_trx_id_and_roll_ptr().
page_zip_dir_add_slot(), page_zip_available(): Add flag "is_clustered",
so that no space will be reserved for TRX_ID and ROLL_PTR on leaf pages
of secondary indexes.
page_zip_apply_log(): Flag an error when val==0 is encoded with two bytes.
page_zip_write_rec(): Add debug assertions that there is enough space
available for the entry before copying the data bytes of the record.
flag of records. The flags may only be updated in heap-allocated
copies of records.
btr_root_raise_and_insert(),
btr_page_split_and_insert(),
btr_cur_insert_if_possible(),
btr_cur_optimistic_insert(),
btr_cur_pessimistic_insert(),
page_cur_tuple_insert(),
page_cur_insert_rec_low(): Add parameters "ext" and "n_ext".
dtuple_convert_big_rec(): Make parameter "ext" const.
page_set_max_trx_id(), page_update_max_trx_id(): Add parameter page_zip.
Check that page_zip_decompress() is never called after modifying the
header or trailer of the compressed page, i.e., that page_zip_decompress()
will restore the uncompressed page as it was before the failed operation.
page_header_reset_last_insert(): Add page_zip parameter.
rec_get_next_ptr(): Return a pointer to the same page, or NULL.
page_dir_delete_slot(): Fix off-by-one errors.
