Added test for PR #19458

Thanks to @DanielEScherzer

ext/opcache/tests/jit/assign_obj_006.phpt

@@ -0,0 +1,37 @@
+--TEST--
+JIT ASSIGN_OBJ: violation of dominance
+--INI--
+opcache.enable=1
+opcache.enable_cli=1
+opcache.file_update_protection=0
+opcache.jit_buffer_size=1M
+--FILE--
+<?php
+class CacheItem {
+    protected mixed $value = null;
+}
+
+function test($value) {
+    $test = Closure::bind(
+        static function ($value) {
+            $item = new CacheItem();
+            if (\is_array($value) && \array_key_exists('value', $value)) {
+                $item->value = $value['value'];
+            }
+            return $item;
+        },
+        null,
+        CacheItem::class);
+    return $test($value);
+}
+
+$values = [['value'=>'str'], ['value'=>'str'], ['value'=>42]];
+$n = count($values);
+
+for ($i = 0; $i < $n; $i++) {
+   test($values[$i]);
+}
+?>
+OK
+--EXPECT--
+OK