Add TimeUnit null check test case in Timed (#5231)

* Add TimeUnit null check test case in Timed

* Correct ugly formatting in BasicIntQueueDisposable

* Reformatting line

* Add blockingIterable’s negative buffer size fail test

* Modify BlockingMultiObserver field’s modfier to private

* revert style, modifier

* Remove duplicated test case.

* Remove no need annotation and variable

src/test/java/io/reactivex/schedulers/TimedTest.java

@@ -84,4 +84,9 @@ public void toStringOf() {
 
         assertEquals("Timed[time=5, unit=SECONDS, value=1]", t1.toString());
     }
+
+    @Test(expected = NullPointerException.class)
+    public void timeUnitNullFail() throws Exception {
+        new Timed<Integer>(1, 5, null);
+    }
 }