JS: move expressions test to box tests

js/js.translator/testData/box/expression/misc/localProperty.kt

@@ -0,0 +1,15 @@
+package foo
+
+val y = 3
+
+fun f(a: Int): Int {
+    val x = 42
+    val y = 50
+
+    return y
+}
+
+fun box(): String {
+    val r = f(y)
+    return if (r == 50) "OK" else "Fail, r = $r"
+}