benchmarks/netperfmeter: Fix build on aarch64
"Too many args to microtask: 17!"
While here:
- Replace desktop-file-utils with shared-mime-info - port doesn't install *.desktop files, but it does install share/mime/packages/netperfmeter.xml.
- Fix warning from portclippy: swap the CMAKE_ON and CMAKE_OFF.
PR: 292237