Add Kotlin & Java destination dirs as output of Android compilation

The compilation outputs of Android compilations accidentally were left
empty. The `destinationDir`s of the Kotlin & Java tasks should be
registered in the `output.classesDirs`.

libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/targets/android/Android25ProjectHandler.kt

@@ -83,6 +83,11 @@ class Android25ProjectHandler(
                 .toTypedArray()
         }
         kotlinTask.javaOutputDir = javaTask.destinationDir
+
+        compilation.output.classesDirs.run {
+            from(project.files(kotlinTask.taskData.destinationDir).builtBy(kotlinTask))
+            from(project.files(project.provider { javaTask.destinationDir }).builtBy(javaTask))
+        }
     }
 
     override fun getSourceProviders(variantData: BaseVariant): Iterable<SourceProvider> =

libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/tasks/Tasks.kt

@@ -139,7 +139,8 @@ abstract class AbstractKotlinCompile<T : CommonCompilerArguments>() : AbstractKo
     @get:Internal
     internal var buildReportMode: BuildReportMode? = null
 
-    private val taskData: KotlinCompileTaskData
+    @get:Internal
+    internal val taskData: KotlinCompileTaskData
         get() = KotlinCompileTaskData.get(project, name)
 
     @get:Input