Add tests for GH-17151

ext/opcache/tests/jit/gh17151_1.phpt

@@ -0,0 +1,22 @@
+--TEST--
+GH-17151: ZEND_FETCH_OBJ_R may modify RC of op1
+--FILE--
+<?php
+
+class C {
+    public function __get($name) {
+        return $this;
+    }
+}
+
+function test() {
+    $x = (new C)->bar;
+    var_dump($x);
+}
+
+test();
+
+?>
+--EXPECTF--
+object(C)#%d (0) {
+}

ext/opcache/tests/jit/gh17151_2.phpt

@@ -0,0 +1,29 @@
+--TEST--
+GH-17151: ZEND_FETCH_OBJ_R may modify RC of op1
+--FILE--
+<?php
+
+class C {
+    public static $prop;
+
+    public function __get($name) {
+        C::$prop = null;
+    }
+
+    public function __destruct() {
+        echo __METHOD__, "\n";
+    }
+}
+
+function test() {
+    C::$prop = new C();
+    C::$prop->bar;
+}
+
+test();
+echo "Done\n";
+
+?>
+--EXPECT--
+C::__destruct
+Done

ext/opcache/tests/jit/gh17151_3.phpt

@@ -0,0 +1,25 @@
+--TEST--
+GH-17151: Method calls may modify RC of ZEND_INIT_METHOD_CALL op1
+--FILE--
+<?php
+
+class C {
+    public static $prop;
+
+    public function storeThis() {
+        self::$prop = $this;
+    }
+}
+
+function test() {
+    $c = new C();
+    $c->storeThis();
+    $c = null;
+}
+
+test();
+
+?>
+===DONE===
+--EXPECT--
+===DONE===