[SPARK-28370][BUILD][TEST] Upgrade Mockito to 2.28.2

## What changes were proposed in this pull request?

This PR aims to upgrade Mockito from **2.23.4** to **2.28.2** in order to bring the latest bug fixes and to be up-to-date for JDK9+ support before Apache Spark 3.0.0. There is Mockito 3.0 released 4 days ago, but we had better wait and see for the stability.

**RELEASE NOTE**
https://github.com/mockito/mockito/blob/release/2.x/doc/release-notes/official.md

**NOTABLE FIXES**
- Configure the MethodVisitor for Java 11+ compatibility (2.27.5)
- When mock is called multiple times, and verify fails, the error message reports only the first invocation (2.27.4)
- Memory leak in mockito-inline calling method on mock with at least a mock as parameter (2.25.0)
- Cross-references and a single spy cause memory leak (2.25.0)
- Nested spies cause memory leaks (2.25.0)
- [Java 9 support] ClassCastExceptions with JDK9 javac (2.24.9, 2.24.3)
- Return null instead of causing a CCE (2.24.9, 2.24.3)
- Issue with mocking type in "java.util.*", Java 12 (2.24.2)

Mainly, Maven (Hadoop-2.7/Hadoop-3.2) and SBT(Hadoop-2.7) Jenkins test passed.

## How was this patch tested?

Pass the Jenkins with the exiting UTs.

Closes #25139 from dongjoon-hyun/SPARK-28370.

Authored-by: Dongjoon Hyun <dhyun@apple.com>
Signed-off-by: Dongjoon Hyun <dhyun@apple.com>

pom.xml

@@ -832,7 +832,7 @@
       <dependency>
         <groupId>org.mockito</groupId>
         <artifactId>mockito-core</artifactId>
-        <version>2.23.4</version>
+        <version>2.28.2</version>
         <scope>test</scope>
       </dependency>
       <dependency>