test: add phpt for ZEND_FUNC_GET_ARGS opline issue

Author: morrisonlevi

profiling/tests/phpt/allocation_func_get_args.phpt

@@ -0,0 +1,53 @@
+--TEST--
+[profiling] sampling shouldn't crash on `ZEND_FUNC_GET_ARGS` opcode
+--DESCRIPTION--
+Beginning with PHP 7.4, the ZEND_FUNC_GET_ARGS opcode doesn't save its opline.
+If it occurs on a new frame before some other opcode has saved the opline, and
+then the allocation profiler triggers (or any other thing which examines
+oplines like the error message when hitting the memory limit), then the
+invalid opline will be accessed, possibly leading to a crash.
+
+Fixed in PHP 8.1.27, 8.2.14 and 8.3.1:
+https://github.com/php/php-src/pull/12768
+
+This test shouldn't crash even on affected versions, because the profiler
+should mitigate the issue with a user opcode handler. However, it's difficult
+to trigger at exactly the right (wrong?) time anyway, so it's unlikely to
+crash anyway.
+TODO: run this in some mode which will look at the opline on every allocation.
+--SKIPIF--
+<?php
+if (PHP_VERSION_ID < 70400)
+    echo "skip: test requires typed properties", PHP_EOL;
+if (!extension_loaded('datadog-profiling'))
+    echo "skip: test requires datadog-profiling", PHP_EOL;
+?>
+--FILE--
+<?php
+
+function ref() {
+    return func_get_args();
+}
+
+class Foo {
+    public static int $i;
+    public static string $s = "x";
+}
+
+var_dump(Foo::$i = "1");
+var_dump(Foo::$s, Foo::$i);
+var_dump(ref('string', 0));
+
+echo 'Done.';
+?>
+--EXPECT--
+int(1)
+string(1) "x"
+int(1)
+array(2) {
+  [0]=>
+  string(6) "string"
+  [1]=>
+  int(0)
+}
+Done.