The Performance Schema identifies temporary tables by assuming that all tables
named with the "#sql" prefix are temporaryand can be ignored. However,
non-temporary tables having the "#sql" prefix are incorrectly identified as
temporary.

To avoid this ambiguity, the Performance Schema will identify temporary tables
using attributes other than the table name, depending on the state:

1) table_share->tmp_table if the share is available and complete, e.g. get_table_share()
2) CREATE: (ha_create_table) Create info flags or explicit boolean for truncated MyISAM temp tables
3) DROP: The filename, guaranteed to have a #sql prefix. Table share not available.

Regardless of the table name, the filenames for temporary and intermediate
tables always have the "#sql" prefix, e.g. "#sql-1234". For non-temporary
tables, a "#" prefix is encoded to @0023 in the filename, e.g. table "#sql_foo"
has the filename "@0023sql_foo."