JS: move more test to box tests

js/js.translator/testData/box/propertyAccess/privatePropertyAccessFromMethod.kt

@@ -0,0 +1,22 @@
+package foo
+
+object A {
+    private val foo = 23
+
+    fun bar(): Int {
+        // Erase object so that we ensure that access to 'foo' property is performed via 'this'
+        // It's no crucial from runtime standpoind, but JS code looks more concise and natural this way.
+        erase()
+        return foo
+    }
+
+    fun erase() {
+        js("_.foo.A = null")
+    }
+}
+
+fun box(): String {
+    var result = A.bar()
+    if (result != 23) return "failed: ${result}"
+    return "OK"
+}