[php-src] Issue #11500: Namespace reuse in createElementNS() generates wrong output

Issue: https://github.com/php/php-src/issues/11500 Author: ausi ### Description The following code: ```php <?php $dom = new \DOMDocument(); $root = $dom->createElementNS('http://example.com', 'root'); $dom->appendChild($root); $a1 = $dom->createElementNS('http://example.com', 'a'); $a1->appendChild($dom->createElementNS('http://example.com', 'b')); $root->appendChild($a1); $a2 = $dom->createElementNS('http://example.com', 'a'); $a2->appendChild($dom->createElementNS('http://example.com', 'b')); $root->appendChild($a2); echo $dom->saveXML(); ``` Resulted in this output: ```xml <?xml version="1.0"?> <root xmlns="http://example.com"><a><b/></a><a><b xmlns="http://example.com"/></a></root> ``` But I expected this output instead: ```xml <?xml version="1.0"?> <root xmlns="http://example.com"><a><b/></a><a><b/></a></root> ``` Only the nightly build from the master branch seems to be affected. With the stable releases this bug does not occur, see https://3v4l.org/hAXOS Related: https://github.com/php/php-src/pull/11428#issuecomment-1600879625 ### PHP Version 8.3.0-dev fe6263e2437b312f9a8b685013cf194f31238a38 ### Operating System _No response_