fil_delete_tablespace(): Remove the unused parameter drop_ahi,
and add the parameter if_exists=false. We want to suppress
error messages if we know that the tablespace has been discarded.
dict_table_rename_in_cache(): Pass the new parameter to
fil_delete_tablespace(), that is, do not complain about
missing tablespace if the tablespace has been discarded.
row_make_new_pathname(): Declare as static.
row_drop_table_for_mysql(): Tolerate !table->data_dir_path
when the tablespace has been discarded.
row_rename_table_for_mysql(): Skip part of the RENAME TABLE
when fil_space_get_first_path() returns NULL.
This is the MariaDB equivalent of fixing the MySQL 5.7 regression
Bug #26935001 ALTER TABLE AUTO_INCREMENT TRIES TO READ
INDEX FROM DISCARDED TABLESPACE
Oracle did not publish a test case, but it is easy to guess
based on the commit message. The MariaDB code is different
due to MDEV-6076 implementing persistent AUTO_INCREMENT.
commit_set_autoinc(): Report ER_TABLESPACE_DISCARDED if the
tablespace is missing.
prepare_inplace_alter_table_dict(): Avoid accessing a discarded
tablespace. (This avoids generating warnings in fil_space_acquire().)
