Reorganize stdlib-js sources specific to the current JS backend

Move kotlin-stdlib-js project and the sources specific to the current backend to 'stdlib/js-v1' directory,
but leave sources that can be shared with the new IR backend in the common 'stdlib/js' location
with exception for 'stdlib/js/src/generated', which is used exclusively for current backend.
This simplifies sourceset configuration when building stdlib with the new backend.

libraries/stdlib/js-ir/runtime/compareTo.kt

@@ -0,0 +1,46 @@
+/*
+ * 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.js
+
+
+// Adopted from misc.js
+
+fun compareTo(a: dynamic, b: dynamic): Int = when (typeOf(a)) {
+    "number" -> when {
+        typeOf(b) == "number" ->
+            doubleCompareTo(a, b)
+        b is Long ->
+            doubleCompareTo(a, b.toDouble())
+        else ->
+            primitiveCompareTo(a, b)
+    }
+
+    "string", "boolean" -> primitiveCompareTo(a, b)
+
+    else -> compareToDoNotIntrinsicify(a, b)
+}
+
+@DoNotIntrinsify
+private fun <T : Comparable<T>> compareToDoNotIntrinsicify(a: Comparable<T>, b: T) =
+    a.compareTo(b)
+
+fun primitiveCompareTo(a: dynamic, b: dynamic): Int =
+    js("a < b ? -1 : a > b ? 1 : 0").unsafeCast<Int>()
+
+fun doubleCompareTo(a: dynamic, b: dynamic): Int =
+    js("""
+    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
+    """).unsafeCast<Int>()