Fix ignore of direct table test files.

[avamingli]

This is introduced by direct table commits, each time run regress test will get files as below.

Untracked files:
  (use "git add <file>..." to include in what will be committed)
        expected/directory_table.out
        expected/directory_table_optimizer.out
        sql/directory_table.sql

Authored-by: Zhang Mingli avamingli@gmail.com

fix #ISSUE_Number

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