[php-src] Issue #21468: Segfault in file_get_contents w/ a https URL and a proxy set

Issue: https://github.com/php/php-src/issues/21468
Author: devicenull

### Description

The following code:

```php
<?php
$opts = [
	'http' => [
		'proxy' => 'example.com:80',
	],
];

$context = stream_context_create($opts);
var_dump(file_get_contents('https://php.net', false, $context));
```

Resulted in this output:
```
Segmentation fault
```

But I expected this output instead:
```
bool(false)
```

This appears to be caused by https://github.com/php/php-src/blob/9b022c4c5c41e203ac91041e15ad01310c09a344/ext/standard/http_fopen_wrapper.c#L579 - there seems to be a missing `if (stream)` context here.

Backtrace looks like this:
```
(gdb) bt
#0  php_stream_url_wrap_http_ex (wrapper=wrapper@entry=0x5555569c8760 <php_stream_http_wrapper>, path=path@entry=0x1555520683b0 "https://php.net", mode=mode@entry=0x55555657a370 "rb", options=options@entry=0,
    context=context@entry=0x155552069480, redirect_max=redirect_max@entry=20, flags=1, response_header=0x7fffffffa920, opened_path=<optimized out>) at /home/builder/php-8.4.19/ext/standard/http_fopen_wrapper.c:573
#1  0x0000555555895359 in php_stream_url_wrap_http (wrapper=0x5555569c8760 <php_stream_http_wrapper>, path=0x1555520683b0 "https://php.net", mode=0x55555657a370 "rb", options=0, opened_path=<optimized out>,
    context=0x155552069480) at /home/builder/php-8.4.19/ext/standard/http_fopen_wrapper.c:1203
#2  0x0000555555923926 in _php_stream_open_wrapper_ex (path=path@entry=0x1555520683b0 "https://php.net", mode=mode@entry=0x55555657a370 "rb", options=8, opened_path=opened_path@entry=0x0, context=0x155552069480)
    at /home/builder/php-8.4.19/main/streams/streams.c:2272
#3  0x000055555587ca02 in zif_file_get_contents (execute_data=<optimized out>, return_value=0x1555520140c0) at /home/builder/php-8.4.19/ext/standard/file.c:414
#4  0x00005555557cfbd4 in zif_phar_file_get_contents (execute_data=0x155552014160, return_value=0x1555520140c0) at /home/builder/php-8.4.19/ext/phar/func_interceptors.c:230
#5  0x0000555555642161 in ZEND_DO_FCALL_SPEC_OBSERVER_HANDLER () at /home/builder/php-8.4.19/Zend/zend_vm_execute.h:2146
#6  0x0000555555642ac8 in execute_ex (ex=0x1555520694a0) at /home/builder/php-8.4.19/Zend/zend_vm_execute.h:58951
#7  0x00005555559ffca3 in zend_execute (op_array=op_array@entry=0x15555208c000, return_value=return_value@entry=0x0) at /home/builder/php-8.4.19/Zend/zend_vm_execute.h:64328
#8  0x0000555555a65580 in zend_execute_script (type=type@entry=8, retval=retval@entry=0x0, file_handle=file_handle@entry=0x7fffffffd050) at /home/builder/php-8.4.19/Zend/zend.c:1934
#9  0x000055555590b606 in php_execute_script_ex (primary_file=<optimized out>, retval=retval@entry=0x0) at /home/builder/php-8.4.19/main/main.c:2578
#10 0x000055555590b917 in php_execute_script (primary_file=<optimized out>) at /home/builder/php-8.4.19/main/main.c:2618
#11 0x0000555555a671cf in do_cli (argc=2, argv=0x555556b0eae0) at /home/builder/php-8.4.19/sapi/cli/php_cli.c:935
#12 0x0000555555648fb6 in main (argc=2, argv=0x555556b0eae0) at /home/builder/php-8.4.19/sapi/cli/php_cli.c:1310
```

### PHP Version

```plain
PHP 8.4.19 (cli) (built: Mar 13 2026 09:22:31) (NTS)
Copyright (c) The PHP Group
Zend Engine v4.4.19, Copyright (c) Zend Technologies
    with Zend OPcache v8.4.19, Copyright (c), by Zend Technologies
```

### Operating System

Debian 13