[php-src] PR #23127: Fix GH-23116 and GH-23117: stack overflow when normalizing a deeply nested document

Pull Request: https://github.com/php/php-src/pull/23127 Author: lazerg DOMNode::normalize() and Dom\Node::normalize() walk the tree by recursing once per element child, so a deeply nested document exhausts the C stack and segfaults. Both now check the stack limit on entry and throw an Error, the same way the XML serializer has since GH-22570. The throw is gated on EG(exception) because these functions return void: without it, unwinding through a tree that is wide at the overflow depth throws once per node and chains the Errors, which is quadratic. Fixes #23116 Fixes #23117