[SPARK-18458][CORE] Fix signed integer overflow problem at an expression in RadixSort.java

## What changes were proposed in this pull request?

This PR avoids that a result of an expression is negative due to signed integer overflow (e.g. 0x10?????? * 8 < 0). This PR casts each operand to `long` before executing a calculation. Since the result is interpreted as long, the result of the expression is positive.

## How was this patch tested?

Manually executed query82 of TPC-DS with 100TB

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

Closes #15907 from kiszk/SPARK-18458.