[php-src] PR #25406: Fix GH-23089: stack overflow in array_merge_recursive()

Pull Request: https://github.com/php/php-src/pull/25406 Author: akasakariko Fixes #23089 Check the Zend stack limit in array_merge_recursive() so deeply nested merges throw an Error before exhausting the native stack, using the same guard as array_replace_recursive() Continues #23091, which was closed without merging; the object cleanup raised in that review is already present through #23340 The original input still encounters the independent array destruction overflow in #15869 during shutdown after reporting the Error, which also reproduces with the merge call removed The regression frees its input iteratively to isolate recursive merging and runs under AddressSanitizer Validation on macOS arm64 - Debug NTS Standard and Zend suite: 8296 passed, 631 skipped, 1 expected failure - Debug ZTS with AddressSanitizer array tests and the next index overflow regression: 840 passed, 14 skipped - Original input with iterative cleanup and tracing JIT: catches Error and exits normally in both builds - Additional ASan stack checks: existing stack_limit_002 and stack_limit_004 Fiber failures reproduced on the unmodified baseline