[clang] [llvm] [CFI] Extract DropTypeTestsPass from LowerTypeTestsPass (PR #192578)

[Peter Collingbourne via cfe-commits]

https://github.com/pcc approved this pull request.

Thanks. I was never happy about this being added in the same pass, it should have been a separate pass from the start.

https://github.com/llvm/llvm-project/pull/192578