Increase task completion timeout from 0.5 => 1.0 sec

As seen at https://travis-ci.org/ReactiveX/RxJavaFX/builds/41017012,
`JavaFxSchedulerTest.testPeriodicScheduling` still fails under Travis
CI, though it is assumed not because of negative delay time values but
because of actual failure to execute tasks in the given half-second
period. This failure is unreproducible on a 4-core MBP, so the 1 second
timeout is a guess.

Author: cbeams

src/test/java/rx/schedulers/JavaFxSchedulerTest.java

@@ -95,7 +95,7 @@ public void call() {
 
         inner.schedulePeriodically(action, 50, 200, TimeUnit.MILLISECONDS);
 
-        if (!latch.await(5000, TimeUnit.MILLISECONDS)) {
+        if (!latch.await(1, TimeUnit.SECONDS)) {
             fail("timed out waiting for tasks to execute");
         }