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/hacks.kt

@@ -0,0 +1,23 @@
+/*
+ * 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
+
+@PublishedApi
+internal fun throwUninitializedPropertyAccessException(name: String): Nothing =
+    throw UninitializedPropertyAccessException("lateinit property $name has not been initialized")
+
+internal fun noWhenBranchMatchedException(): Nothing = throw NoWhenBranchMatchedException()
+
+
+fun THROW_ISE() {
+    throw IllegalStateException()
+}
+fun THROW_CCE() {
+    throw ClassCastException()
+}
+fun THROW_NPE() {
+    throw NullPointerException()
+}