Thanks for reporting!  I cannot reproduce this test
failure,though.  Looking at the posted test script, there might be
an issue regarding the character encoding, since the extension_dir
is a/é/w (UTF-8), but the comment above states that the file is
required to be encoded in iso-8859-1.  Can you please
double-check, that the file's encoding is what it is supposed to
be?  Furthermore, for debugging purposes, it might be helpful to
insert a `var_dump($out);` after `$out = shell_exec($cmd);` to be
able to see in bug71273.out what was actually reported by PHP.

I checked the file encoding with git bash and it says it's encoded in ISO-8859. Since this test passes on the NTS builds, I checked what the file was encoded for that and it is ISO-8859. So I believe the file being encoded as ISO-8859 is correct. 

The output after adding 'var_dump($out)' for TS builds: 
int(0)
NULL
==DONE==


Compared to NTS builds: 
int(1)
string(450) "PHP Warning:  PHP Startup: Unable to load dynamic library 'php_kartoffelbrei.dll' (tried: a/�/w\php_kartoffelbrei.dll (The specified module could not be found.), a/�/w\php_php_kartoffelbrei.dll.dll (The specified module could not be found.)) in Unknown on line 0
PHP 7.3.6 (cli) (built: May 29 2019 12:12:14) ( NTS MSVC15 (Visual C++ 2017) x64 )
Copyright (c) 1997-2018 The PHP Group
Zend Engine v3.3.6, Copyright (c) 1998-2018 Zend Technologies
"
==DONE==

Thanks for checking!

Unless being able to reproduce the test failure, I can only guess
that php_escape_html_entities() with ENT_HTML_SUBSTITUTE_ERRORS[1]
fails.  This needs further investigation.

[1] <https://github.com/php/php-src/blob/php-7.3.6/main/main.c#L949>

May be related to this bug. (PHP 7.2 -)

opcache On : zend_extension=php_opcache.dll

array (size=5)
  'Error' => boolean true
  0 => int 48
  1 => int 255
  2 => string '7.2.19' (length=6)
  3 => string 'apache2handler' (length=14)

opcache Off

array (size=5)
  'Error' => boolean false
  0 => int 48
  1 => int 48
  2 => string '7.2.19' (length=6)
  3 => string 'apache2handler' (length=14)

test php code
<?php
$s = '012345';
var_dump(['Error'=>ord('0')!==ord($s[0]), ord('0'), ord($s[0]),
          PHP_VERSION, PHP_SAPI]);

> May be related to this bug. (PHP 7.2 -)

Unlikely, since this ticket is about an issue that happens
regardless of opcache on/off.

Please file a new tew ticket, and try to provide more information,
since I cannot reproduce: <https://3v4l.org/8SLkb>.

I apologize for the late feedback. Using the latest 7.3 build (7.3.11), this test does not fail anymore. It seems to have been fixed or an error on my end at the time.