Turn ok_for_lower_case_names() to a method in Lex_ident_fs

#ifndef DBUG_OFF

/**

  Verifies that database/table name is in lowercase, when it should be

  This is supposed to be used only inside DBUG_ASSERT()

*/

bool Lex_ident_fs::ok_for_lower_case_names() const

{

  if (!lower_case_table_names || !str)

    return true;

  DBNameBuffer buf(*this, lower_case_table_names);

  return cmp(*this, buf.to_lex_cstring()) == 0;

}

#endif

bool lock_object_name(THD *thd, MDL_key::enum_mdl_namespace mdl_type,

                      const char *db, const char *name)

                      const LEX_CSTRING &db, const LEX_CSTRING &name);

Events::drop_schema_events(THD *thd, const LEX_CSTRING &db_lex);

bool lock_db_routines(THD *thd, const LEX_CSTRING &db);

int sp_drop_db_routines(THD *thd, const LEX_CSTRING &db);

void Query_cache::invalidate(THD *thd, const LEX_CSTRING &db)