JS: create new common directory for all generated tests, migrate several tests there

js/js.translator/testData/box/classObject/objectInCompanionObject.kt

@@ -0,0 +1,25 @@
+// See KT-6203
+package foo
+
+class TestClass {
+    object a {
+        override fun toString() = "a"
+    }
+
+    companion object {
+        object b {
+            override fun toString() = "b"
+        }
+    }
+
+    fun test() = convert(a) + convert(b)
+}
+
+fun convert(o: Any) = o.toString()
+
+fun box(): String {
+    assertEquals("ab", TestClass().test())
+    assertEquals("ab2", convert(TestClass.a) + convert(TestClass.Companion.b) + "2")
+
+    return "OK"
+}