MDEV-21804 Assertion `marked_for_read()' failed upon INSERT into table with long unique blob under binlog_row_image=NOBLOB

Problem:- Calling mark_columns_per_binlog_row_image() earlier may change the
result of mark_virtual_columns_for_write() , Since it can set the bitmap on
for virtual column, and henceforth  mark_virtual_column_deps(field) will
never be called in mark_virtual_column_with_deps.

This bug is not specific for long unique, It also fails for this case
   create table t2(id int primary key, a blob, b varchar(20) as (LEFT(a,2)));