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

js/js.translator/testData/box/closure/closureInNestedFunctionsWhichMixedWithObject.kt

@@ -0,0 +1,13 @@
+package foo
+
+fun box(): String {
+    val t = myRun {
+        object {
+            fun boo(param: String): String {
+                return myRun { param }
+            }
+        }
+    }
+
+    return t.boo("OK")
+}