JS: move expressions test to box tests

js/js.translator/testData/box/expression/when/whenWithIf.kt

@@ -0,0 +1,26 @@
+package foo
+
+fun box(): String {
+
+    var c = when(3) {
+        3 -> 1
+        2 -> 100
+        else -> 100
+    } + when (2) {
+        1 -> 100
+        else -> 1
+    } + when (0) {
+        1 -> if (true) 100 else 100
+        0 -> if (false) {
+            100
+        }
+        else {
+            1
+        }
+        else -> 100
+    }
+
+    if (c != 3) return "fail"
+
+    return "OK"
+}