[clang] [lldb] Use CLANG_RESOURCE_DIR more consistently (PR #103388)

[Kim Gräsman via cfe-commits]

kimgr wrote:

> > Do we need anything more to make progress with this PR?
> 
> @kimgr Do you have committer permission? Would you like some help to get this merged?

Oh, no, I don't, I would need someone to merge this for me. It's still pretty early in the v.20 cycle, right, so maybe this is a good time to try and see if it sticks?

https://github.com/llvm/llvm-project/pull/103388