Refact stdlib generator, add support for different backends

[JS IR BE] Runtime fixes
 * Do not generate external declarations for IR BE
 * Move `arrayToString` helper function out of shared JS stdlib
 * Fix arrays type check for IR BE

libraries/stdlib/js/src/js/polyfills.js

@@ -288,12 +288,27 @@ if (typeof ArrayBuffer.isView === "undefined") {
     }
 
     // Patch sort to work with TypedArrays if needed.
+    // TODO: consider to remove following function and replace it with `Kotlin.doubleCompareTo` (see misc.js)
+    var totalOrderComparator = function (a, b) {
+        if (a < b) return -1;
+        if (a > b) return 1;
+
+        if (a === b) {
+            if (a !== 0) return 0;
+
+            var ia = 1 / a;
+            return ia === 1 / b ? 0 : (ia < 0 ? -1 : 1);
+        }
+
+        return a !== a ? (b !== b ? 0 : 1) : -1
+    };
+
     for (var i = 0; i < arrays.length; ++i) {
         var TypedArray = arrays[i];
         if (typeof TypedArray.prototype.sort === "undefined") {
             Object.defineProperty(TypedArray.prototype, 'sort', {
                 value: function(compareFunction) {
-                    return Array.prototype.sort.call(this, compareFunction);
+                    return Array.prototype.sort.call(this, compareFunction || totalOrderComparator);
                 }
             });
         }

libraries/stdlib/js/src/kotlin/collections.kt

@@ -6,7 +6,6 @@
 package kotlin.collections
 
 import kotlin.comparisons.naturalOrder
-import kotlin.internal.InlineOnly
 import kotlin.random.Random
 
 /** Returns the array if it's not `null`, or an empty array otherwise. */
@@ -50,10 +49,6 @@ internal actual fun <T> copyToArrayImpl(collection: Collection<*>, array: Array<
     return array
 }
 
-@library("arrayToString")
-@Suppress("UNUSED_PARAMETER")
-internal fun arrayToString(array: Array<*>): String = definedExternally
-
 /**
  * Returns an immutable list containing only the specified object [element].
  */

libraries/stdlib/js/src/kotlin/collectionsExternal.kt

@@ -0,0 +1,10 @@
+/*
+ * Copyright 2010-2018 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license
+ * that can be found in the license/LICENSE.txt file.
+ */
+
+package kotlin.collections
+
+@library("arrayToString")
+@Suppress("UNUSED_PARAMETER")
+internal fun arrayToString(array: Array<*>): String = definedExternally