Increasing Unit Test Timeout for Slow Machines

- Increasing timeout by a lot to handle slow machines such as this: https://netflixoss.ci.cloudbees.com/job/RxJava-pull-requests/629/testReport/junit/rx.schedulers/ExecutorSchedulerTests/recursionUsingFunc2/
- The timeout is only there if a deadlock or memory leak occurs (which is what this PR is fixing) so when everything is healthy it does not timeout

Author: benjchristensen

rxjava-core/src/test/java/rx/schedulers/AbstractSchedulerConcurrencyTests.java

@@ -163,7 +163,7 @@ public Subscription call(Scheduler innerScheduler, Long i) {
         assertEquals(10, counter.get());
     }
 
-    @Test(timeout = 8000)
+    @Test(timeout = 20000)
     public void recursionUsingFunc2() throws InterruptedException {
         final CountDownLatch latch = new CountDownLatch(1);
         getScheduler().schedule(1L, new Func2<Scheduler, Long, Subscription>() {
@@ -185,7 +185,7 @@ public Subscription call(Scheduler innerScheduler, Long i) {
         latch.await();
     }
 
-    @Test(timeout = 8000)
+    @Test(timeout = 20000)
     public void recursionUsingAction0() throws InterruptedException {
         final CountDownLatch latch = new CountDownLatch(1);
         getScheduler().schedule(new Action1<Action0>() {