[llvm] [bazel] Clean up unused exported files (PR #114620)

[Jordan Rupprecht via llvm-commits]

rupprecht wrote:

Sorry for not getting to this review earlier. I would have approved it though. Thanks @pranavk for the build fix!

Files often end up in exports_files because some other package needs it, and I'd wager it's often the case due to uses only outside of the LLVM tree. So removing things from exports_files just because there are no in tree uses is often going to break things.

That said, it's trivial to just add them back, preferably w/ a comment explaining that it's needed outside of the tree, so removing entries LGTM.

https://github.com/llvm/llvm-project/pull/114620