Add isFrozen test on object

kotlin-native/backend.native/tests/codegen/objectDeclaration/isFrozen.kt

@@ -0,0 +1,27 @@
+/*
+ * Copyright 2010-2021 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license
+ * that can be found in the LICENSE file.
+ */
+
+package codegen.objectDeclaration.isFrozen
+
+import kotlin.test.*
+import kotlin.native.concurrent.*
+
+object X {
+    var value: Int = 0
+}
+
+@Test fun runTest() {
+    if (Platform.memoryModel == MemoryModel.STRICT) {
+        assertTrue(X.isFrozen)
+        assertFailsWith<InvalidMutabilityException> {
+            X.value = 42
+        }
+        assertEquals(0, X.value)
+    } else {
+        assertFalse(X.isFrozen)
+        X.value = 42
+        assertEquals(42, X.value)
+    }
+}