[php-src] Issue #9456: finfo_file returns wrong mime type for some pdf files

Issue: https://github.com/php/php-src/issues/9456 Author: Darhakexge ### Description finfo_file returns incorrect mime type on pdf files that have leading spaces in the first line. The following code: ```php <?php $finfo = new \finfo(\FILEINFO_MIME_TYPE)); $mimeType = $finfo->file($path); echo $mimeType; ``` Resulted in this output: ``` "application/octet-stream" ``` But I expected this output instead: ``` expected result is: "application/pdf" ``` While debugging I found that if the file has leading spaces in the first line finfo_file can't get the mimetype correctly. Removing the spaces manually allows finfo_file get the mime type as expected ```diff - %PDF-1.7 <-- Notice the space at the beginning +%PDF-1.7 1 0 obj << /Type /Catalog /Outlines 2 0 R /Pages 3 0 R >> endobj ... ``` ### PHP Version 8.1.9 ### Operating System Ubuntu 18.04, Ubuntu 20.04, Windows 10, Windows 11