Typo3 9.5.2: Install tool crashes using PHP 7.3

Rene Bangemann reported an issue

Machine: 4.9.0-8-686 #1 (closed) SMP Debian 4.9.130-2 (2018-10-27) i686 GNU/Linux

Apache: 2.4.25 PHP: 7.3.0-1+020181206202713.23+stretch1.gbp076afd (cli) (built: Dec 6 2018 20:27:14) ( NTS )

After manually creating the directory typo3temp and executing typo3/install.php the execution stops after some seconds with a blank page. In the apache error log the following message is shown:

[Tue Dec 11 23:27:37.586396 2018] [core:notice] [pid 638] AH00052: child pid 4799 exit signal Illegal instruction (4)

Another test with PHP and Composer 1.8 shows the error message "Ungültiger Maschinenbefehl".

According to https://get.typo3.org/version/9#system-requirements PHP 7.3 is supported.

Reported URL:https://my.typo3.org/

User Agent:Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:64.0) Gecko/20100101 Firefox/64.0