[SPARK-23424][SQL] Add codegenStageId in comment

## What changes were proposed in this pull request?

This PR always adds `codegenStageId` in comment of the generated class. This is a replication of #20419  for post-Spark 2.3.
Closes #20419

```
/* 001 */ public Object generate(Object[] references) {
/* 002 */   return new GeneratedIteratorForCodegenStage1(references);
/* 003 */ }
/* 004 */
/* 005 */ // codegenStageId=1
/* 006 */ final class GeneratedIteratorForCodegenStage1 extends org.apache.spark.sql.execution.BufferedRowIterator {
/* 007 */   private Object[] references;
...
```

## How was this patch tested?

Existing tests

Author: Kazuaki Ishizaki <ishizaki@jp.ibm.com>

Closes #20612 from kiszk/SPARK-23424.