[FIR-TEST] Add new testdata generated after changes in previous commit

compiler/testData/diagnostics/tests/objects/OpenInObject.fir.kt

@@ -0,0 +1,9 @@
+object Obj {
+    fun foo() {}
+
+    open fun bar() {}
+
+    var x: Int = 0
+
+    open var y: Int = 1
+}