test(aot): 添加魔术常量、字符串插值和变量函数的AOT测试

- 添加magic-constants.phpt测试文件验证__LINE__、__FILE__、__DIR__、__FUNCTION__、__METHOD__、__CLASS__常量
- 添加string-interpolation.phpt测试文件验证复杂表达式的字符串插值功能
- 添加variable-functions.phpt测试文件验证可变函数调用和回调存储功能
- 添加variable-variables.phpt测试文件验证$$var语法并标记为跳过（AOT不支持）

tests/aot/magic-constants.phpt

@@ -0,0 +1,37 @@
+--TEST--
+Magic constants: __LINE__, __FILE__, __DIR__, __FUNCTION__, __METHOD__, __CLASS__
+--FILE--
+<?php
+
+class TestMagicConst {
+    public function testMethod() {
+        echo "__METHOD__: "; var_dump(__METHOD__);
+        echo "__CLASS__: "; var_dump(__CLASS__);
+        echo "__FUNCTION__: "; var_dump(__FUNCTION__);
+    }
+}
+
+function testFunction() {
+    echo "__FUNCTION__ in function: "; var_dump(__FUNCTION__);
+}
+
+function main() {
+    echo "__LINE__: "; var_dump(__LINE__);
+    echo "__FILE__: "; var_dump(basename(__FILE__));
+    echo "__DIR__: "; var_dump(basename(__DIR__));
+
+    testFunction();
+
+    $obj = new TestMagicConst();
+    $obj->testMethod();
+}
+
+?>
+--EXPECTF--
+__LINE__: int(%d)
+__FILE__: string(%d) "magic-constants.php"
+__DIR__: string(%d) "aot"
+__FUNCTION__ in function: string(%d) "testFunction"
+__METHOD__: string(%d) "TestMagicConst::testMethod"
+__CLASS__: string(%d) "TestMagicConst"
+__FUNCTION__: string(%d) "testMethod"

tests/aot/string-interpolation.phpt

@@ -0,0 +1,38 @@
+--TEST--
+String interpolation with complex expressions
+--FILE--
+<?php
+
+class Person {
+    public string $name;
+    public function __construct(string $name) {
+        $this->name = $name;
+    }
+}
+
+function main() {
+    $count = 5;
+    $arr = [1, 2, 3];
+
+    // Simple variable interpolation
+    $s1 = "count is $count";
+    var_dump($s1);
+
+    // Array access interpolation
+    $s2 = "first: {$arr[0]}, last: {$arr[2]}";
+    var_dump($s2);
+
+    // Property access interpolation
+    $person = new Person("Alice");
+    $s3 = "Name: {$person->name}";
+    var_dump($s3);
+
+    echo "done\n";
+}
+
+?>
+--EXPECT--
+string(10) "count is 5"
+string(17) "first: 1, last: 3"
+string(11) "Name: Alice"
+done

tests/aot/variable-functions.phpt

@@ -0,0 +1,41 @@
+--TEST--
+Variable functions
+--FILE--
+<?php
+
+function greet(string $name): string {
+    return "Hello, " . $name;
+}
+
+function sum(int $a, int $b): int {
+    return $a + $b;
+}
+
+function main() {
+    // Variable function call
+    $func = 'greet';
+    $result = $func("World");
+    var_dump($result);
+
+    // Variable function with multiple args
+    $math = 'sum';
+    var_dump($math(3, 7));
+
+    // Callable stored in variable
+    $callable = 'strlen';
+    var_dump($callable("test"));
+
+    // Array of callables
+    $ops = ['sum'];
+    var_dump($ops[0](10, 20));
+
+    echo "done\n";
+}
+
+?>
+--EXPECT--
+string(12) "Hello, World"
+int(10)
+int(4)
+int(30)
+done

tests/aot/variable-variables.phpt

@@ -0,0 +1,16 @@
+--TEST--
+Variable variables ($$var)
+--SKIPIF--
+<?php
+echo "skip The \$\$ syntax is not supported in AOT";
+?>
+--FILE--
+<?php
+
+$a = "hello";
+$$a = "world";
+var_dump($hello);
+
+?>
+--EXPECT--
+string(5) "world"