Try to simply lit config file generation by adding standalone fedora specific
config file. In the future, when we need to customize the lit config
for the llvm-test package, we can just update lit.fedora.cfg.py rather
than trying to patch the default config from the spec file.
This patch also makes the run-lit-tests script identical on all arches,
so it will no longer cause multi-lib conflicts.
dd29ab70a3