fix: return db name for I_S.TABLES(and others) in original letter case.
if mysql starts with lower_case_table_names=1 | 2 then original db name is converted
to lower case(for I_S tables). It happens when we perform add_table_to_list.
to avoid this we make a copy of original db name and use the copy hereafter.
Added support for lower_case_table_names=2, which is to be used on case insensitive file systems.
This tells MySQL to preserve the used case of filenames and database names to make it esier to move files between cases sensitive can case insensitive file systems (like Windows and Linux)
