JS: move expressions test to box tests

js/js.translator/testData/box/expression/stringTemplates/stringValues.kt

@@ -0,0 +1,19 @@
+package foo
+
+// test String template must have one or more entries.
+public class Fe {
+    fun open(method: String, url: String, async: Boolean = true, user: String = "", password: String = "") = "$method $url $async $user $password"
+}
+
+fun box(): String {
+    val a = "abc"
+    val b = "def"
+    val message = "a = $a, b = $b"
+
+    if (message != "a = abc, b = def") return "fail"
+
+    val v1 = null
+    if ("returns null null" != "returns $v1 ${null}") return "fail"
+
+    return if (Fe().open("22", "33") == "22 33 true  ") "OK" else "fail"
+}