A year or so ago, I re-wrote most of the lit infrastructure in LLVM so that it wasn't so boilerplate-y. I added lots of common helper type stuff, simplifed usage patterns, and made the code more elegant and maintainable.
We migrated to this in LLVM, clang, and lld's lit files, but not in LLDBs. This started to bite me recently, as the 4 most recent times I tried to run the lit test suite in LLDB on a fresh checkout the first thing that would happen is that python would just start crashing with unhelpful backtraces and I would have to spend time investigating.
You can reproduce this today by doing a fresh cmake generation, doing ninja lldb and then python bin/llvm-lit.py -sv ~/lldb/lit/SymbolFile at which point you'll get a segfault that tells you nothing about what your problem is.
I started trying to fix the issues with bandaids, but it became clear that the proper solution was to just bring in the work I did in the rest of the projects. The side benefit of this is that the lit configuration files become much cleaner and more understandable as a result.