JS: move more test to box tests

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

@@ -0,0 +1,15 @@
+package foo
+
+var a: Int
+
+
+    get() {
+        return 5
+    }
+    set(b) {
+
+    }
+
+fun box(): String {
+    return if (a == 5) "OK" else "fail: $a"
+}