MDEV-30882 Crash on ROLLBACK in a ROW_FORMAT=COMPRESSED table

row_upd_rec_in_place(): Avoid calling page_zip_write_rec() if we
are not modifying any fields that are stored in compressed format.

btr_cur_update_in_place_zip_check(): New function to check if a
ROW_FORMAT=COMPRESSED record can actually be updated in place.

btr_cur_pessimistic_update(): If the BTR_KEEP_POS_FLAG is not set
(we are in a ROLLBACK and cannot write any BLOBs), ignore the potential
overflow and let page_zip_reorganize() or page_zip_compress() handle it.
This avoids a failure when an attempted UPDATE of an NULL column to 0 is
rolled back. During the ROLLBACK, we would try to move a non-updated
long column to off-page storage in order to avoid a compression failure
of the ROW_FORMAT=COMPRESSED page.

page_zip_write_trx_id_and_roll_ptr(): Remove an assertion that would fail
in row_upd_rec_in_place() because the uncompressed page would already
have been modified there.

Thanks to Jean-François Gagné for providing a copy of a page that
triggered these bugs on the ROLLBACK of UPDATE and DELETE.

A 10.6 version of this was tested by Matthias Leich using
cmake -DWITH_INNODB_EXTRA_DEBUG=ON a.k.a. UNIV_ZIP_DEBUG.

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