[Java] Fix warning.

Author: mjpt777

sbe-tool/src/test/java/uk/co/real_logic/sbe/FieldAccessOrderCheckTest.java

@@ -42,6 +42,7 @@ public class FieldAccessOrderCheckTest
  private final MutableDirectBuffer buffer = new ExpandableArrayBuffer();
  private final MessageHeaderEncoder messageHeaderEncoder = new MessageHeaderEncoder();
  private final MessageHeaderDecoder messageHeaderDecoder = new MessageHeaderDecoder();
+ private final Random random = new Random();
 
  @BeforeAll
  static void assumeDebugMode()
@@ -53,7 +54,7 @@ static void assumeDebugMode()
  @BeforeEach
  void setUp()
  {
- new Random().nextBytes(buffer.byteArray());
+ random.nextBytes(buffer.byteArray());
  }
 
  @Test