[JS IR BE] fix compilation of stdlib by IR BE after move coroutine related sources in stdlib

libraries/stdlib/js/irRuntime/hacks.kt

@@ -5,6 +5,8 @@
 
 package kotlin
 
+import kotlin.coroutines.experimental.SequenceBuilder
+
 // TODO: Ignore FunctionN interfaces
 
 public interface Function0<out R> : Function<R> {
@@ -25,3 +27,8 @@ public interface Function3<in P1, in P2, in P3, out R> : Function<R> {
 
 public inline fun <reified T> arrayOfNulls(size: Int): Array<T?> = js("[]")  // FIXME: Implement
 
+internal inline fun <T> buildSequence(noinline builderAction: suspend SequenceBuilder<T>.() -> Unit): Sequence<T> =
+    kotlin.coroutines.experimental.buildSequence(builderAction)
+
+internal inline fun <T> buildIterator(noinline builderAction: suspend SequenceBuilder<T>.() -> Unit): Iterator<T> =
+    kotlin.coroutines.experimental.buildIterator(builderAction)