[FLINK-23255] Force JUnit 4 version to 4.13.2 to avoid Threading issues. See junit-team/junit4#1517

Author: PatrickRen

pom.xml

@@ -202,6 +202,13 @@ under the License.
 			<scope>test</scope>
 		</dependency>
 
+		<dependency>
+			<groupId>junit</groupId>
+			<artifactId>junit</artifactId>
+			<version>${junit4.version}</version>
+			<scope>test</scope>
+		</dependency>
+
 		<dependency>
 			<groupId>org.mockito</groupId>
 			<artifactId>mockito-core</artifactId>