tests: Add 'application/x-iso' as valid mimetype for ISO files
Some mirrors return 'application/x-iso' for ISO images.
$ curl --head --location https://ftp.riken.jp/Linux/fedora/releases/37/Server/aarch64/iso/Fedora-Server-netinst-aarch64-37-1.7.iso
HTTP/1.1 200 OK
Date: Tue, 04 Jul 2023 23:17:05 GMT
Server: Apache
Last-Modified: Sat, 05 Nov 2022 05:43:03 GMT
ETag: "284cc800-5ecb2a9f25d0b"
Accept-Ranges: bytes
Content-Length: 676120576
X-FRAME-OPTIONS: SAMEORIGIN
X-XSS-Protection: 1; mode=block
X-Content-Type-Options: nosniff
Content-Type: application/x-iso
Fixes: #121 (closed)
Signed-off-by: sid sidtosh4@gmail.com
Edited by Sid T