Move Comparator to kotlin.comparisons and make it imported by default.

#KT-2084

compiler/frontend/src/org/jetbrains/kotlin/resolve/TargetPlatform.kt

@@ -43,6 +43,7 @@ abstract class TargetPlatform(val platformName: String) {
             add(ImportPath("kotlin.ranges.*"))
             add(ImportPath("kotlin.sequences.*"))
             add(ImportPath("kotlin.text.*"))
+            add(ImportPath("kotlin.comparisons.Comparator"))
         }
 
         override val platformConfigurator =

js/js.libraries/src/core/Comparator.kt

@@ -0,0 +1,26 @@
+/*
+ * Copyright 2010-2016 JetBrains s.r.o.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package kotlin.comparisons
+
+
+public interface Comparator<T> {
+    @JsName("compare") fun compare(a: T, b: T): Int
+}
+
+public inline fun <T> Comparator(crossinline comparison: (T, T) -> Int): Comparator<T> = object : Comparator<T> {
+    override fun compare(a: T, b: T): Int = comparison(a, b)
+}

js/js.libraries/src/core/javautil.kt

@@ -16,14 +16,6 @@
 
 package java.util
 
-interface Comparator<T> {
-    @JsName("compare") fun compare(a: T, b: T): Int
-}
-
-inline fun <T> Comparator(crossinline comparison: (T, T) -> Int): Comparator<T> = object : Comparator<T> {
-    override fun compare(a: T, b: T): Int = comparison(a, b)
-}
-
 
 // TODO: Not supported
 // typealias Date = kotlin.js.Date

libraries/stdlib/src/kotlin/comparisons/TypeAliases.kt

@@ -0,0 +1,5 @@
+@file:kotlin.jvm.JvmVersion
+
+package kotlin.comparisons
+
+public typealias Comparator<T> = java.util.Comparator<T>