[lit] Don't norm case when inserting into the config map.

This makes all paths lowercase on Windows, which seemed like a
good idea at the time, but it means that tests can't properly
use FileCheck to match expected path names.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@313889 91177308-0d34-0410-b5e6-96231b3b80d8
5 files changed