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

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

@@ -0,0 +1,18 @@
+package foo
+
+interface B {
+    fun result(): Int
+}
+
+class A(private val x: Int) {
+    fun test() = object : B {
+        val y = x + 1
+
+        override fun result() = x * 10 + y
+    }
+}
+
+fun box(): String {
+    assertEquals(23, A(2).test().result())
+    return "OK"
+}