fix restore for count(*)

What problem does this PR solve?

Before this commit, select count(*) from t will be restored to select count(1) from t. After this commit, select count(*) from t can be restored to select count(*) from t correctly

What is changed and how it works?

Check List

Tests

Unit test

Code changes

Has exported function/method change

Side effects

N/A

Related changes

Need to cherry-pick to the release branch

pingcap / parser

fix restore for count(*) #1240

What problem does this PR solve?

What is changed and how it works?

Check List