JS backend: translate labeled for expressions.

#KT-2986 fixed

(cherry picked from commit b0836a6)

js/js.translator/testFiles/expression/for/cases/labeledFor.kt

@@ -0,0 +1,14 @@
+package foo
+
+val a1 = arrayOfNulls<Int>(0)
+
+fun box(): Boolean {
+    var bar = 33
+    @outer for (a in array(1, 2)) {
+        for (b in array(1, 4)) {
+            break @outer
+        }
+        bar = 42
+    }
+    return bar == 33;
+}