[php-src] Issue #21029: [ARM64] zend_mm_heap corrupted with ZTS builds (Static PHP 8.5.2)

Issue: https://github.com/php/php-src/issues/21029
Author: maks-oleksyuk

### Description

On **ARM64 (aarch64) architecture**, ZTS builds of PHP 8.5.2 cause `zend_mm_heap corrupted` errors when running Laravel Pint. The same code works fine on **x86_64**.

**Cross-platform comparison:**

| Architecture | Build                | Result                                  |
|--------------|----------------------|-----------------------------------------|
| **x86_64**   | Static PHP 8.5.2 ZTS | ✅ Works                                 |
| **aarch64**  | Static PHP 8.5.2 ZTS | ❌ Crashes with `zend_mm_heap corrupted` |

**Key details:**
- Built with: `zig 0.15.2`
- ZTS (Zend Thread Safety): **enabled**
- Architecture: **aarch64** (ARM64 - Apple Silicon M4)

## Minimal Reproduction Case

Laravel Pint can be used as a reliable reproduction case:

```bash
# Install Pint
composer require laravel/pint

# Run version command - this crashes on ARM64 ZTS
php vendor/bin/pint --version
```

**Expected output:**
```
Pint 1.27.0
```

**Actual output on ARM64 ZTS:**
```
zend_mm_heap corrupted
bash: line 1:  2005 Aborted                 ( php vendor/bin/pint --version )
exit status 134
```

## Workaround

Setting `USE_ZEND_ALLOC=0` environment variable fixes the issue:

```bash
USE_ZEND_ALLOC=0 php vendor/bin/pint --version
# Output: Pint 1.27.0
```

This forces PHP to use system memory allocator (malloc) instead of Zend Memory Manager.

## PHP Configuration

```
memory_limit => 1024M
Zend Memory Manager => enabled
ZTS => yes
JIT => Disabled
```

The same PHP version (8.5.2 ZTS) works fine on x86_64 but fails on aarch64

### PHP Version

```plain
PHP 8.5.2 (cli) (built: Jan 16 2026 02:41:43) (ZTS zig 0.15.2 aarch64)
Copyright (c) The PHP Group
Built by Static PHP <https://static-php.dev> #StandWithUkraine
Zend Engine v4.5.2, Copyright (c) Zend Technologies
    with Zend OPcache v8.5.2, Copyright (c), by Zend Technologies
```

### Operating System

MacOS Tahoe 26.2