[SPARK-32767][SQL] Bucket join should work if spark.sql.shuffle.partitions larger than bucket number
### What changes were proposed in this pull request?
Bucket join should work if `spark.sql.shuffle.partitions` larger than bucket number, such as:
```scala
spark.range(1000).write.bucketBy(432, "id").saveAsTable("t1")
spark.range(1000).write.bucketBy(34, "id").saveAsTable("t2")
sql("set spark.sql.shuffle.partitions=600")
sql("set spark.sql.autoBroadcastJoinThreshold=-1")
sql("select * from t1 join t2 on t1.id = t2.id").explain()
```
Before this pr:
```
== Physical Plan ==
*(5) SortMergeJoin [id#26L], [id#27L], Inner
:- *(2) Sort [id#26L ASC NULLS FIRST], false, 0
: +- Exchange hashpartitioning(id#26L, 600), true
: +- *(1) Filter isnotnull(id#26L)
: +- *(1) ColumnarToRow
: +- FileScan parquet default.t1[id#26L] Batched: true, DataFilters: [isnotnull(id#26L)], Format: Parquet, PartitionFilters: [], PushedFilters: [IsNotNull(id)], ReadSchema: struct<id:bigint>, SelectedBucketsCount: 432 out of 432
+- *(4) Sort [id#27L ASC NULLS FIRST], false, 0
+- Exchange hashpartitioning(id#27L, 600), true
+- *(3) Filter isnotnull(id#27L)
+- *(3) ColumnarToRow
+- FileScan parquet default.t2[id#27L] Batched: true, DataFilters: [isnotnull(id#27L)], Format: Parquet, PartitionFilters: [], PushedFilters: [IsNotNull(id)], ReadSchema: struct<id:bigint>, SelectedBucketsCount: 34 out of 34
```
After this pr:
```
== Physical Plan ==
*(4) SortMergeJoin [id#26L], [id#27L], Inner
:- *(1) Sort [id#26L ASC NULLS FIRST], false, 0
: +- *(1) Filter isnotnull(id#26L)
: +- *(1) ColumnarToRow
: +- FileScan parquet default.t1[id#26L] Batched: true, DataFilters: [isnotnull(id#26L)], Format: Parquet, PartitionFilters: [], PushedFilters: [IsNotNull(id)], ReadSchema: struct<id:bigint>, SelectedBucketsCount: 432 out of 432
+- *(3) Sort [id#27L ASC NULLS FIRST], false, 0
+- Exchange hashpartitioning(id#27L, 432), true
+- *(2) Filter isnotnull(id#27L)
+- *(2) ColumnarToRow
+- FileScan parquet default.t2[id#27L] Batched: true, DataFilters: [isnotnull(id#27L)], Format: Parquet, PartitionFilters: [], PushedFilters: [IsNotNull(id)], ReadSchema: struct<id:bigint>, SelectedBucketsCount: 34 out of 34
```
### Why are the changes needed?
Spark 2.4 support this.
### Does this PR introduce _any_ user-facing change?
No.
### How was this patch tested?
Unit test.
Closes #29612 from wangyum/SPARK-32767.
Authored-by: Yuming Wang <yumwang@ebay.com>
Signed-off-by: Wenchen Fan <wenchen@databricks.com>
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