## What changes were proposed in this pull request?
This is to fix a bug in #23036 that would cause a join hint to be applied on node it is not supposed to after join reordering. For example,
```
val join = df.join(df, "id")
val broadcasted = join.hint("broadcast")
val join2 = join.join(broadcasted, "id").join(broadcasted, "id")
```
There should only be 2 broadcast hints on `join2`, but after join reordering there would be 4. It is because the hint application in join reordering compares the attribute set for testing relation equivalency.
Moreover, it could still be problematic even if the child relations were used in testing relation equivalency, due to the potential exprId conflict in nested self-join.
As a result, this PR simply reverts the join reorder hint behavior change introduced in #23036, which means if a join hint is present, the join node itself will not participate in the join reordering, while the sub-joins within its children still can.
## How was this patch tested?
Added new tests
Closes#23524 from maryannxue/query-hint-followup-2.
Authored-by: maryannxue <maryannxue@apache.org>
Signed-off-by: gatorsmile <gatorsmile@gmail.com>
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