[Gradle] Create kotlinOptions during task init and keep outputFile for js

This is so that existing build scripts using
withType() do not break. Also, fix the failing
test.

It was necessary to keep outputFile for the js compile task
as it was accessed from the build scripts. Instead, a new
property is introduced which uses Gradle lazy properties.

libraries/tools/kotlin-gradle-plugin-api/src/main/kotlin/org/jetbrains/kotlin/gradle/dsl/KotlinCompile.kt

@@ -6,8 +6,10 @@
 package org.jetbrains.kotlin.gradle.dsl
 
 import groovy.lang.Closure
+import org.gradle.api.Action
 import org.gradle.api.Task
 import org.gradle.api.tasks.Internal
+import org.gradle.util.ConfigureUtil
 
 interface KotlinCompile<out T : KotlinCommonOptions> : Task {
     @get:Internal
@@ -17,8 +19,11 @@ interface KotlinCompile<out T : KotlinCommonOptions> : Task {
         kotlinOptions.fn()
     }
 
+    fun kotlinOptions(fn: Action<in T>) {
+        fn.execute(kotlinOptions)
+    }
+
     fun kotlinOptions(fn: Closure<*>) {
-        fn.delegate = kotlinOptions
-        fn.call()
+        ConfigureUtil.configure(fn, kotlinOptions)
     }
 }