BUG #17091: Cannot install with EDB installer when username contains diacritics

The following bug has been logged on the website:

Bug reference:      17091
Logged by:          Paul Guyot
Email address:      pguyot@kallisys.net
PostgreSQL version: 13.3
Operating system:   Windows 10
Description:

A user has diacritics in her account name (her first name is Jaunė with last
character being U+0117).

Installation with latest EDB Installer fails with the following message (in
French) :
> Une erreur s'est produite
> Erreur dans l'execution de C:\\Windows\System32\icacls
"C:\\Users\...\Temp/postgresql_installer_random" /T /Q /grand
"azuread\jaune(OI)(CI)F": azuread\jaune: Le mappage entre les noms de compte
et les ID de sécurité n'a pas été effectué.

When exected in a shell, the reported icacls command line fails with the
same error message.

I believe the install script fails here:

https://github.com/EnterpriseDB/edb-installers/blob/2bb85e7ef6203a48989991ab659c961a72aa05b6/server/installer.xml.in#L139

${whoami} is taken from C:\\Windows\System32\whoami

Interestingly, when invoking C:\\Windows\System32\whoami in the shell, we
get the username with diacritics (azuread\jaunė) instead of the username
without diacritics in the error message. To be more precise, there are
diacritics in the paths and these appear properly in the error message.

When executed with this username, the icacls command line returns another
error (which would translate to "Access refused"), but I guess this is
because the command line was not executed with the proper rights.