Add tests from ilutov

Author: nikic

Zend/tests/readonly_props/override_with_attributes.phpt

@@ -0,0 +1,26 @@
+--TEST--
+Can override readonly property with attributes
+--FILE--
+<?php
+
+#[Attribute]
+class FooAttribute {}
+
+class A {
+    public readonly int $prop;
+
+    public function __construct() {
+        $this->prop = 42;
+    }
+}
+class B extends A {
+    #[FooAttribute]
+    public readonly int $prop;
+}
+
+var_dump((new ReflectionProperty(B::class, 'prop'))->getAttributes()[0]->newInstance());
+
+?>
+--EXPECT--
+object(FooAttribute)#1 (0) {
+}

Zend/tests/readonly_props/visibility_change.phpt

@@ -0,0 +1,30 @@
+--TEST--
+Visibility can change in readonly property
+--FILE--
+<?php
+
+class A {
+    protected readonly int $prop;
+
+    public function __construct() {
+        $this->prop = 42;
+    }
+}
+class B extends A {
+    public readonly int $prop;
+}
+
+$a = new A();
+try {
+    var_dump($a->prop);
+} catch (Error $error) {
+    echo $error->getMessage() . "\n";
+}
+
+$b = new B();
+var_dump($b->prop);
+
+?>
+--EXPECT--
+Cannot access protected property A::$prop
+int(42)