## What changes were proposed in this pull request?

When fixing schema field names using escape characters with `addReferenceMinorObj()` at [SPARK-18952](https://issues.apache.org/jira/browse/SPARK-18952) (#16361), double-quotes around the names were remained and the names become something like `"((java.lang.String) references[1])"`.

```java
/* 055 */     private int maxSteps = 2;
/* 056 */     private int numRows = 0;
/* 057 */     private org.apache.spark.sql.types.StructType keySchema = new org.apache.spark.sql.types.StructType().add("((java.lang.String) references[1])", org.apache.spark.sql.types.DataTypes.StringType);
/* 058 */     private org.apache.spark.sql.types.StructType valueSchema = new org.apache.spark.sql.types.StructType().add("((java.lang.String) references[2])", org.apache.spark.sql.types.DataTypes.LongType);
/* 059 */     private Object emptyVBase;
```

We should remove the double-quotes to refer the values in `references` properly:

```java
/* 055 */     private int maxSteps = 2;
/* 056 */     private int numRows = 0;
/* 057 */     private org.apache.spark.sql.types.StructType keySchema = new org.apache.spark.sql.types.StructType().add(((java.lang.String) references[1]), org.apache.spark.sql.types.DataTypes.StringType);
/* 058 */     private org.apache.spark.sql.types.StructType valueSchema = new org.apache.spark.sql.types.StructType().add(((java.lang.String) references[2]), org.apache.spark.sql.types.DataTypes.LongType);
/* 059 */     private Object emptyVBase;
```

## How was this patch tested?

Existing tests.

Author: Takuya UESHIN <ueshin@databricks.com>

Closes #19491 from ueshin/issues/SPARK-22273.

(cherry picked from commit e0503a7223410289d01bc4b20da3a451730577da)
Signed-off-by: gatorsmile <gatorsmile@gmail.com>