update failing test to match recently updated result file

mysql-test/t/lowercase_table2.test

@@ -251,7 +251,7 @@ let $MYSQLD_DATADIR= `select @@datadir`;
 --echo # Check that still there is an entry for table in TDC.
 show open tables like 't_bug44738_%';
 --echo # So attempt to create table with the same name should fail.
---error ER_FILE_NOT_FOUND
+--error ER_TABLE_EXISTS_ERROR
 create table t_bug44738_UPPERCASE (i int);
 --echo # And should succeed after FLUSH TABLES.
 flush tables;