This is a follow-up for the initial MDEV-24486 commit. It renames
the view sys.table_privileges to sys.privileges_by_table_by_level
and adds some more tests displaying privilege levels GLOBAL and SCHEMA
The existing INFORMATION_SCHEMA.TABLE_PRIVILEGES displays only those
privileges that were specifically granted on the table level,
whereas it may be useful to see privileges granted at the database
and global level.
This commit adds a new view `table_privileges` to the `sys` schema
for that purpose. The view shows privileges on existing tables
and views, combining all possible levels:
- user_privileges
- schema_privileges
- table_privileges
* it isn't "pfs" function, don't call it Item_func_pfs,
don't use item_pfsfunc.*
* tests don't depend on performance schema, put in the main suite
* inherit from Item_str_ascii_func
* use connection collation, not utf8mb3_general_ci
* set result length in fix_length_and_dec
* do not set maybe_null
* use my_snprintf() where possible
* don't set m_value.ptr on every invocation
* update sys schema to use the format_pico_time()
* len must be size_t (compilation error on Windows)
* the correct function name for double->double is fabs()
* drop volatile hack
