Fix phpGH-13177: PHP 8.3.2: final private constructor not allowed when used in trait

zend_compile has an exception to this rule for constructors using
`zend_is_constructor`, which compares the function name to
`__construct`. Sadly, `zend_is_constructor` is not a public API, but we
can just do the string compare ourselves.

Author: nielsdos

Zend/tests/traits/bugs/gh13177.phpt

@@ -0,0 +1,50 @@
+--TEST--
+GH-13177 (PHP 8.3.2: final private constructor not allowed when used in trait)
+--FILE--
+<?php
+
+trait Bar {
+    final private function __construct() {}
+}
+
+final class Foo1 {
+    use Bar;
+}
+
+final class Foo2 {
+    use Bar {
+        __construct as final;
+    }
+}
+
+class Foo3 {
+    use Bar {
+        __construct as final;
+    }
+}
+
+for ($i = 1; $i <= 3; $i++) {
+    $rc = new ReflectionClass("Foo$i");
+    echo $rc->getMethod("__construct"), "\n";
+}
+
+class Foo4 extends Foo3 {
+    private function __construct() {}
+}
+
+?>
+--EXPECTF--
+Method [ <user, ctor> final private method __construct ] {
+  @@ %sgh13177.php 4 - 4
+}
+
+Method [ <user, ctor> final private method __construct ] {
+  @@ %sgh13177.php 4 - 4
+}
+
+Method [ <user, ctor> final private method __construct ] {
+  @@ %sgh13177.php 4 - 4
+}
+
+
+Fatal error: Cannot override final method Foo3::__construct() in %s on line %d

Zend/zend_inheritance.c

@@ -1949,7 +1949,7 @@ static void zend_add_trait_method(zend_class_entry *ce, zend_string *name, zend_
 	zend_function *new_fn;
 	bool check_inheritance = false;
 
-	if ((fn->common.fn_flags & (ZEND_ACC_PRIVATE | ZEND_ACC_FINAL)) == (ZEND_ACC_PRIVATE | ZEND_ACC_FINAL)) {
+	if ((fn->common.fn_flags & (ZEND_ACC_PRIVATE | ZEND_ACC_FINAL)) == (ZEND_ACC_PRIVATE | ZEND_ACC_FINAL) && !zend_string_equals_literal_ci(name, ZEND_CONSTRUCTOR_FUNC_NAME)) {
 		zend_error(E_COMPILE_WARNING, "Private methods cannot be final as they are never overridden by other classes");
 	}