meson: Use separate lists for non-ivf test files

Meson 1.3.0 deprecates [0] str.format() use with File objects [1].
Starting with 1.4.0 [2] there will be an explicit method [3] to query
the path.
Alternatively, fs.name() from the FS module could be used for meson
versions >= 0.59.0. [4]
Since our minimum version is 0.49.0 though, we'll use this workaround.

[0] https://mesonbuild.com/Release-notes-for-1-3-0.html#unified-message-strformat-and-fstring-formatting
[1] https://github.com/mesonbuild/meson/issues/12406
[2] https://github.com/mesonbuild/meson/pull/12408
[3] https://mesonbuild.com/Reference-manual_returned_file.html#filefull_path
[4] https://mesonbuild.com/Fs-module.html#name