fix(test): Each test class that use JFX must init the JFX toolkit

Author: arnobl

src/test/java/io/reactivex/rxjavafx/schedulers/JavaFxSchedulerTest.java

@@ -58,10 +58,13 @@ public void start(Stage primaryStage) throws Exception {
         }
     }
 
-    @BeforeClass
-    public static void initJFX() {
-        javafx.application.Platform.startup(() ->{});
-    }
+	@BeforeClass
+	public static void initJFX() {
+		try {
+			javafx.application.Platform.startup(() ->{});
+		}catch(final IllegalStateException ignore) {
+		}
+	}
 
     @Test
     public void testPeriodicScheduling() throws Exception {

src/test/java/io/reactivex/rxjavafx/sources/JavaFxObservableTest.java

@@ -36,6 +36,14 @@
 
 public final class JavaFxObservableTest {
 
+	@BeforeClass
+	public static void initJFX() {
+		try {
+			javafx.application.Platform.startup(() ->{});
+		}catch(final IllegalStateException ignore) {
+		}
+	}
+
     @Test
     public void testIntervalSource() {