tests: Programmatically generate the tests sysroots
When we build a debian package of steam-runtime-tools, due to the debian
source format 3.0 (native), all our .so
test files are stripped down.
To avoid losing them we generate the fake-icds
and fake-icds-flatpak
sysroots from the python script generate-sysroots.py
.
Addresses T26709