JS: move more test to box tests

js/js.translator/testData/box/multiFile/classesInheritedFromOtherFile.kt

@@ -0,0 +1,26 @@
+// FILE: a.kt
+package foo
+
+open class A() {
+    open fun f() = 3;
+}
+
+open class C() : B() {
+    override fun f() = 5
+}
+
+
+// FILE: b.kt
+package foo
+
+open class B() : A() {
+    override fun f() = 4
+}
+
+fun box(): String {
+    if (A().f() != 3) return "fail1"
+    if (B().f() != 4) return "fail2"
+    if (C().f() != 5) return "fail3"
+
+    return "OK"
+}