JS: move expressions test to box tests

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

@@ -0,0 +1,15 @@
+package foo
+
+
+fun box(): String {
+    var result = "fail1"
+    var i = 1
+    do
+        when (i) {
+            1 ->    result = "OK"
+            else -> result = "fail2"
+        }
+    while (i==0)
+    return result
+}
+