Meson complains:
../src/intel/decoder/meson.build:67: DEPRECATION: Project uses feature that was always broken, and is now deprecated since '1.3.0': str.format: Value other than strings, integers, bools, options, dictionaries and lists thereof..
So instead of trying to format a file, change gentest_xml to store just
the string. Need to adapt genxml_path to consider the current source
dir, but everything else works like before.
Reviewed-by: Dylan Baker <dylan@pnwbakers.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/27706>
