[5.5] Clear "select" bindings whenever select columns have been override.

[wanghanlin]

Sorry for not writing a detailed description in last PR #21485

This PR revert some changes in last fix #21468. And add the code call ->setBindings([], 'select') when select() being called to fix an issue for cases query builder originally have select bindings but later being override cause a binding mismatch issue that lead to error.

The quickest way to reproduce error is run this in tinker

$query = app('Illuminate\Database\Query\Builder')->selectRaw('(select count(*) from posts where status = ?)', [1])->from('users');

$query will have bindings [1].
if later call

$query->select()->where('foo', 'bar');

$query will have bindings [1, "bar"] while it supposed to only have ["bar"]

@themsaid let me know your thoughts, thanks!

reference: #21472

[themsaid]

The case referenced is not a bug, you're overriding your select statement, I'd consider this is an edge case but not a bug.

The reason why we can't add this to select() is it might break applications in a patch release, if you want you can submit this to the master branch so we take the time to test if it's breaking or not.

[wanghanlin]

ok! I will create a PR once 5.5 is merged to master.