Update RxJava2 version to 2.1.9

Author: elizarov

reactive/kotlinx-coroutines-rx2/build.gradle

@@ -1,6 +1,6 @@
 dependencies {
     compile project(':kotlinx-coroutines-reactive')
-    compile 'io.reactivex.rxjava2:rxjava:2.0.6'
+    compile 'io.reactivex.rxjava2:rxjava:2.1.9'
 }
 
 tasks.withType(dokka.getClass()) {

reactive/kotlinx-coroutines-rx2/src/test/kotlin/kotlinx/coroutines/experimental/rx2/Check.kt

@@ -16,9 +16,7 @@
 
 package kotlinx.coroutines.experimental.rx2
 
-import io.reactivex.Maybe
-import io.reactivex.Observable
-import io.reactivex.Single
+import io.reactivex.*
 
 fun <T> checkSingleValue(
     observable: Observable<T>,
@@ -33,7 +31,8 @@ fun checkErroneous(
         checker: (Throwable) -> Unit
 ) {
     val singleNotification = observable.materialize().blockingSingle()
-    checker(singleNotification.error)
+    val error = singleNotification.error ?: error("Excepted error")
+    checker(error)
 }
 
 fun <T> checkSingleValue(

reactive/kotlinx-coroutines-rx2/src/test/kotlin/kotlinx/coroutines/experimental/rx2/ObservableSingleTest.kt

@@ -16,13 +16,11 @@
 
 package kotlinx.coroutines.experimental.rx2
 
-import io.reactivex.Observable
-import kotlinx.coroutines.experimental.CommonPool
-import kotlinx.coroutines.experimental.runBlocking
-import org.junit.Assert.assertEquals
-import org.junit.Assert.fail
-import org.junit.Test
-import java.util.concurrent.TimeUnit
+import io.reactivex.*
+import kotlinx.coroutines.experimental.*
+import org.junit.*
+import org.junit.Assert.*
+import java.util.concurrent.*
 
 /**
  * Tests emitting single item with [rxObservable].
@@ -73,7 +71,7 @@ class ObservableSingleTest {
         }
 
         checkErroneous(observable) {
-            assert(it is IllegalArgumentException)
+            assertTrue(it is IllegalArgumentException)
         }
     }
 
@@ -187,7 +185,7 @@ class ObservableSingleTest {
         }
 
         checkErroneous(observable) {
-            assert(it is IllegalStateException)
+            assertTrue(it is IllegalStateException)
             assertEquals("OK", it.message)
         }
     }