Migrated tests in devtools/build/lib/concurrent to JUnit 4.

--
MOS_MIGRATED_REVID=108983674

src/test/java/com/google/devtools/build/lib/concurrent/KeyedLockerTest.java

diff --git a/src/test/java/com/google/devtools/build/lib/concurrent/KeyedLockerTest.java b/src/test/java/com/google/devtools/build/lib/concurrent/KeyedLockerTest.java
index 173e712..f08396c 100644
--- a/src/test/java/com/google/devtools/build/lib/concurrent/KeyedLockerTest.java
+++ b/src/test/java/com/google/devtools/build/lib/concurrent/KeyedLockerTest.java
@@ -49,14 +49,14 @@
   protected abstract KeyedLocker<String> makeFreshLocker();
 
   @Before
-  public void setUp_KeyedLockerTest() {
+  public final void setUp_KeyedLockerTest() {
     locker = makeFreshLocker();
     executorService = Executors.newFixedThreadPool(NUM_EXECUTOR_THREADS);
     wrapper = new ThrowableRecordingRunnableWrapper("KeyedLockerTest");
   }
 
   @After
-  public void tearDown() {
+  public final void shutdownExecutor() throws Exception  {
     locker = null;
     MoreExecutors.shutdownAndAwaitTermination(executorService, TestUtils.WAIT_TIMEOUT_SECONDS,
         TimeUnit.SECONDS);

src/test/java/com/google/devtools/build/lib/concurrent/MoreFuturesTest.java

diff --git a/src/test/java/com/google/devtools/build/lib/concurrent/MoreFuturesTest.java b/src/test/java/com/google/devtools/build/lib/concurrent/MoreFuturesTest.java
index d842480..b8fbe35 100644
--- a/src/test/java/com/google/devtools/build/lib/concurrent/MoreFuturesTest.java
+++ b/src/test/java/com/google/devtools/build/lib/concurrent/MoreFuturesTest.java
@@ -47,12 +47,12 @@
   private ExecutorService executorService;
 
   @Before
-  public void setUp() throws Exception {
+  public final void createExecutor() throws Exception  {
     executorService = Executors.newFixedThreadPool(5);
   }
 
   @After
-  public void tearDown() throws Exception {
+  public final void shutdownExecutor() throws Exception  {
     MoreExecutors.shutdownAndAwaitTermination(executorService, TestUtils.WAIT_TIMEOUT_SECONDS,
         TimeUnit.SECONDS);