Add test for readonly classes emitted in PHP 8.3

Author: thekid

src/test/php/lang/ast/unittest/emit/PHP83Test.class.php

@@ -0,0 +1,18 @@
+<?php namespace lang\ast\unittest\emit;
+
+use lang\ast\emit\Type;
+use test\{Assert, Test};
+
+class PHP83Test extends EmittingTest {
+
+  /** @return string */
+  protected function runtime() { return 'php:8.3.0'; }
+
+  #[Test]
+  public function readonly_classes() {
+    Assert::matches(
+      '/readonly class [A-Z0-9]+{/',
+      $this->emit('readonly class %T { }')
+    );
+  }
+}